i have an 89 360 tbi engine.i want to build it to make 400 streetable hp.i would like to be around 9.5 to 1 comp.also im going to carberate it.i have a holley street domminator intake.it will be going into a 67 dart with 3.55 gears.how would you guys build it?also want to stay with the 308 heads that are on it.thanks mike
89 360
- Thread starter amcmike
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Locomotion
Well-Known Member
400hp shouldn't be a problem even if you stay conservative. But some of the other members will have better suggestions and/or first-hand experiences on a street/strip build-up than I can give. Your '89 360 should already have the 308 heads!
Open air clean atop a 750 cfm, I'm not sure on the intake. Post a picture if you can. The comp. ratio is good. If not a half point high. The cam can be a simple 280 duration comp. Use headers with 2-1/2 exhaust pipe size.
The heads should be pocket ported at least and use 2.02 - 1.60 valves for a good top end. They'll need to be able to flow well. If the exhaust flow is short, under 70% of the intake, use a dual pattern cam. A simalr intake duration with more exhaust duation is good to do. An Extreme cam will work.
The heads should be pocket ported at least and use 2.02 - 1.60 valves for a good top end. They'll need to be able to flow well. If the exhaust flow is short, under 70% of the intake, use a dual pattern cam. A simalr intake duration with more exhaust duation is good to do. An Extreme cam will work.
BJR Racing
Well-Known Member
I agree, But I would leave the small valves as this will give more torque and low end power, and will be much more drivable. The bigger valves will kill the bottom end. The small valves are good to 6500rpms anyway, and this isn't really a street engine any more at these rpms. But I would gasket match and bowl blend them, then decide on which cam that you are going to use. Most cams that are streetable aren't going to be over .525 lift anyway, so putting the bigger valves in is a waste of time for low lifts as the bigger valves are ment for higher lifts. Smaller valves will out flow bigger valves at low lifts and be some what even in higher lifts. Also by keeping the smaller valves the efficentcy will be higher in the heads and make more power, fuel useage will be less too.
The exhaust flow should be in the 80-85% range from the factory so this shouldn't be a problem.
BJR Racing
The exhaust flow should be in the 80-85% range from the factory so this shouldn't be a problem.
BJR Racing
The 308s are reportably the best swirl port LA head mopar made before changing to the magnum heads. in 91-92. I'm using them on a 360 stroker for more race than street so went with the 202 intake valves. As BJR has said, stay with the stock size valve - or if they need replacing due to the number of previous valve grinds - go to 1.94 dia. to bring the valve back up to virgin height in the combustion chamber. Get a good 3-4 angle valve job and a bowl hog, a little blending and your good to go.
If you want to send me an email direct I will share some other thoughts/recommendations for you to consider. [email protected]
If you want to send me an email direct I will share some other thoughts/recommendations for you to consider. [email protected]
moper
Well-Known Member
I would just do a good performance rebuild. ,030 over, KB hypers, stock crank and resized rods w/ARP bolts. I wouldnt bother with the windage tray, it wasnt desgned for 3.58 stroke, and it's much less effective because of it. For heads, the 308s are fine. I'd install the 2.202s, to put the seats out further, and the longer stroke doesnt loose low end like a 318/340 will. I'd also clean up the bowls, and gasket match them. For a cam, that '89 has the hyd roller in it..Replace it, or have it reground for performance, and run it. Another thought would be Magnum heads, with the 1.6 ratio rockers, and great chamber/ports... Prob can get it done very nicely, for around $3600.
BJR makes a good point on valves size. Though i suggested 2.02's, I found no real seat of the pants difference. Dyno runs may very well support his suggestion. True, You did say very streetable, I have had no problems with 2.02's in the head @ low RPM's. He is taking a port velocity route over volume. This will really help in the combustion and in a heavy car. Not that A bodys are heavy.
Key thing here is not only velocity, but good flow and amount in volume consumable to make the power. There just needs to be enuff CFM in the head flow to suport the power level is what I'm trying to say.
Is this a roller engine block? I didn't even think of that.
Moper, 360's came with windage trays and the idea of not being designed for it may be true, since 360's were not around when they were put on the 340's, but it is still effective. Weather a MoPar unit or a Milodon, it's cheap or free HP.
Oil control is HP. Many peole don't know about the sheild for the valley to keep oil off the intake. Cooler intake ='s HP.
Key thing here is not only velocity, but good flow and amount in volume consumable to make the power. There just needs to be enuff CFM in the head flow to suport the power level is what I'm trying to say.
Is this a roller engine block? I didn't even think of that.
Moper, 360's came with windage trays and the idea of not being designed for it may be true, since 360's were not around when they were put on the 340's, but it is still effective. Weather a MoPar unit or a Milodon, it's cheap or free HP.
Oil control is HP. Many peole don't know about the sheild for the valley to keep oil off the intake. Cooler intake ='s HP.
BJR Racing
Well-Known Member
The problem with the magnum heads is that they oil through the pushrods, and not the block. As for the 360 haveing enough stroke for the bigger valves and that you wouldn't see the difference, if this was the case then they should have put them in from the factory as machining would have been cheaper. Once again the cam that is going to be used is more than likely going to be a low lift, a street/strip type. The bigger valve loses velocity and flow at low lifts this is why the factory used a smaller valve in the cars when produced.
I/we have tried this on a 318 with 360 heads and the 360 heads were done the same as the 318 heads, bowl blended and gasket matched, the 318s were gasket matched to the 360 gaskets. The 360 heads were 40HP loss on the 318 and when we went back to the 318 heads the car picked right up. Even though the 318 had 1.78 intake valves and the 360 had 1.88 valves. The port on the 360 cc'ed at 150 and the 318 cc'ed at 132, the air flow on the 360 was 234 cfms and the 318 was 213 cfms, the problem came from the velocity as the smaller valve and the smaller port was more efficient than the bigger one. Both air flows were at .400 because most cams for the street aren't much bigger than this, and .500 is more suited for racing applications. Here are some #s that I have come up with on 2 very well ported 360 heads.
lift 2.02 1.88
.100 94 96
.200 177 185
.300 223 229
.400 251 248
.500 287 283
.600 287 285
.700 285 281
The 2.02 has a efficentcy rating of 59.1% and the 1.88 has a rating of 68.4% the difference comes because of the valve size. As you can see there isn't much difference in the air flows, but you have to look at the low lift #s as this is where most of the valve action happens. Also with the smaller valve the velocity rating will be much higher due to the valve size. If you can get/make the same air flow as a bigger valve then the smaller valve will make more power and be faster, and more fuel efficent.
The 2.02 head has a 167cc runner and the 1.88 has a 165cc runner, so the work in the ports is the same just the difference in the valve size to make the port difference.
BJR Racing
I/we have tried this on a 318 with 360 heads and the 360 heads were done the same as the 318 heads, bowl blended and gasket matched, the 318s were gasket matched to the 360 gaskets. The 360 heads were 40HP loss on the 318 and when we went back to the 318 heads the car picked right up. Even though the 318 had 1.78 intake valves and the 360 had 1.88 valves. The port on the 360 cc'ed at 150 and the 318 cc'ed at 132, the air flow on the 360 was 234 cfms and the 318 was 213 cfms, the problem came from the velocity as the smaller valve and the smaller port was more efficient than the bigger one. Both air flows were at .400 because most cams for the street aren't much bigger than this, and .500 is more suited for racing applications. Here are some #s that I have come up with on 2 very well ported 360 heads.
lift 2.02 1.88
.100 94 96
.200 177 185
.300 223 229
.400 251 248
.500 287 283
.600 287 285
.700 285 281
The 2.02 has a efficentcy rating of 59.1% and the 1.88 has a rating of 68.4% the difference comes because of the valve size. As you can see there isn't much difference in the air flows, but you have to look at the low lift #s as this is where most of the valve action happens. Also with the smaller valve the velocity rating will be much higher due to the valve size. If you can get/make the same air flow as a bigger valve then the smaller valve will make more power and be faster, and more fuel efficent.
The 2.02 head has a 167cc runner and the 1.88 has a 165cc runner, so the work in the ports is the same just the difference in the valve size to make the port difference.
BJR Racing
thanks for the replies.this is what i'm thinking right now.pistons-speed pro h116cp-30 should give me around 9.5 to 1,i have'nt pulled the intake yet to see if its a roller cam or not.if its not i'm thinking of xe268h.if it is a roller i'm looking at the new retro-fit hydrolic roller cams that compcams are comming out with,specs xr274hr-10, in. [email protected] 538 lift, ex. [email protected] 534 lift.i will be doing the port cleanup myself,i want to do the best i can without a flowbench.any tips? some pics? measurements? on porting the 308s.i'm leaning towards the 1.88 or 1.94 from what you guys posted already.ps,those are interesting flow numbers you posted BJR.thanks mike
BJR Racing
Well-Known Member
Mike, I would use the 1.88s if the seats aren't too bad, I think that you ment 1.92s but either way the smaller will be better for the street. Give me your e-mail address and I'll send you some pics of some commandos and the way that it should look, but keep in mind that these are aluminums but the work is still the same.
I would also use the the XR274HR-10 cam. I have some heads here that I could get some shots of and send them to you also but they'er not finished as of yet, but still show you the work that has to be done. In fact they are the heads that the flow #s are from.
More than likely the engine that you have is going to be a roller unless someone has changed the cam before you got it.
BJR Racing
I would also use the the XR274HR-10 cam. I have some heads here that I could get some shots of and send them to you also but they'er not finished as of yet, but still show you the work that has to be done. In fact they are the heads that the flow #s are from.
More than likely the engine that you have is going to be a roller unless someone has changed the cam before you got it.
BJR Racing
BJR; The oil through pushrods. Have you had any problems with them? Raced them?
Wondering about cave eats you might have crossed.
Wondering about cave eats you might have crossed.
BJR Racing
Well-Known Member
No I haven't had any problems, they are just a copy of the sbc pushrods. This setup that the magnums have is very similar to the oldsmobile engine from the past. Comp cams has been building this type of setup for years for them.(olds) In fact I believe that comp cams is making this setup for the magnums now, if not mopar has them. They kind of remind me of the ford 302-351 steup that crane cams offered in kit form. Mopar sells it in kit form also,with roller rockers.
BJR Racing
BJR Racing
moper
Well-Known Member
I wont debate 2.02 vs. 1.88 vs 1.94. I run 2.02s or larger in all my small blocks,except 318s. I'll agree to disagree..lol. As far as oiling thru the pushrods for magnums, it's a better way to oil the top end. Mopar didn't use it, but change to a roller cam, or even many flat tappet designs with roller rockers, and you'll find the first order of business is to limit the oiling to the top end, because the mopar design robs the low end, to feed the top, and the top, doesnt need that much..It adds to windage, and doesnt drain back very quickly. So, if you're buying a cam, and then lifters, buy the AMC lifters and correct pushrods, and you're done. You would need to either buy the MP intake or have your Magnum heads re-drilled for the early bolt pattern tho. (easy to do). If you buy a windage tray, buy the milodon. It's head and shoulders above the MP unit, and it will be more effective, regardless of the stroke. The MP one tends to trap oil around the 3.58" stroke, as opposed to directing it away with the 3.31" stroke. The crank/rods come too close to it. Also, the MP one should have it's slot enlarged too. Just an opinion...lol
Moper, you said;
Have you tested it yourself or seen a mag print this?
I've noted you think there a wate. Also noted you like the milodon. The thing I like here is there a company that can afford to spend money on a part to do it right without the worry's that a parent company has on cost of low production parts or longevity of the part to be used.
But you trash one and praise another with what base of facts or writin mag write ups?
Short of dyno testing windage trays back to back, you would need a camera to see whats goin on in there. :laughing:
The end sentence is killer. Just an opinion! How can you write this like it's fact and then end with "it's just an opinion?
Have you tested it yourself or seen a mag print this?
I've noted you think there a wate. Also noted you like the milodon. The thing I like here is there a company that can afford to spend money on a part to do it right without the worry's that a parent company has on cost of low production parts or longevity of the part to be used.
But you trash one and praise another with what base of facts or writin mag write ups?
Short of dyno testing windage trays back to back, you would need a camera to see whats goin on in there. :laughing:
moper
Well-Known Member
I call it an opinion, because it's just that. I suppose every desktop dyno junkey has 100% fact too. I happen to be building a couple of larger stroke A engines right now for customers, and thought it wise to reasearch a litle more in depth. This includes talking to several A engine bracket racers, and reading thru the latest book on big inch mopar small blocks..Just out a couple of monthes ago. Milodon make a beter peice. It's not a peice of steelwith a few small louvers in it. It has larger cut outs, and when using ARP studs, acan be properly fit over the larger strokes. The racers I spoke with (2, not 400) said in dyno comparisons, they found NO GAIN by installing the factory style trays, and in one case, had bearing issues because there was a ton of oil (IN HIS OPINION) gettting trapped around the rotating assembly. His engine doesnt have upper end restiction, but does use bushed lifetr bores. So, oil would run down thru the valley, and go right onto the crank. He eliminated the issue by using sheilds to direct oil around the cam better, and by REMOVING the MP windage tray. the end result was no power loss, and no bearing marks. I dont feel the need to include what I do to verify my stuff. I don't say anything unless I beive there is truth to it. I also dont pretend to know even 1/2 of what a lot of builders know. I do what works for me, and my customers. If you really want to trash me, I'll add that the 360 in my dart, has an MP tray I installed, and (gasp) didnt enlarge the slots on. I built it 2 years ago..I didnt know what I know now. And I'm sure, by next spring, I will have learned more about it. The day you start thinking you know how it all works best, is the day before you start loosing..lol. BTW, NEVER ask a magazine...lol. I'll say whatever anyone wants if they want to pay me too..
No sir no sir no sir.
BWa ha ha ha ha
True true true. Must stay open minded.
I think giving examples or reasoning is giving credit. True, not every reply should have to have one. However, next time you find something new that no one else is doing or has done, you'll come up and say something about it's improvment. Including what was done should be an explaintion of a few facts and findings and how where whys etc... not only does this help explain, but lends well unto itslef in a wider scope.
Otherwise, it seems to be a open ended statement of bologna.
How many times have you seen some ya-hoo show up and state a mod thats completely rediculous and you know it.
It's confusing when you say it's an opinion and back it up with facts from racers dyno runs.
This route takes credit away from the engineers whom built it and the corp from installing it on there engines. Would the factory install a worthless part on there cars at there expense so a few racers would purchase them.
It's not like they only did a few engines on a few cars and called a special part for the Hi-po cars only makeing it a rare OE part to find.
It's certainly not a cost effective way for the company to generate sales on there own aftermarket program.
The "Lets install a million of these things so we can sell a few thousand to racer" While they know it doesn't help and possibly know it could be a hinderance.
Beyond a shadow of a doubt, not only myself, but others here now and later will look foward to your results. (Not being a dick here about it, but just honest) My God bless your wallet for dyno runs! I can not afford to do them. The best thing I can do is go to the track for a time slip.
I'd just also like to take the time here and say I think your advice given here is good and helpful. I don't want to start in with you or anybody here.
I also apologize for coming off like a dick if I did.
BJR Racing
Well-Known Member
I think that if we all were to get together and talk that we would all have different opinions as to what would work best. But this is just the way that it is, and this is why we have competition, partly to see who is better, but then this is only on a given day as tomorrow it will be someone elses turn. So if a part works for you then use it, but this doesn't mean that it will work for the next guy, as people are as different as engine combinations. Along with there needs and goals.
No one should have to explain in complete detail as some secrets are to be kept, this is what drives business. Someone is always going to be better than the next guy, but take the best pionts from the one that you believe is telling you what you want to do and go with it.
I will tell anyone anything that they want to know, (if I can) I just WONT tell how to do it, this is the business part of it, with 25+ years of experience, you tend to learn something both good and bad. The only way to learn is to make mistakes, then find out why so you don't go it again, or at least try not to.
BJR Racing
No one should have to explain in complete detail as some secrets are to be kept, this is what drives business. Someone is always going to be better than the next guy, but take the best pionts from the one that you believe is telling you what you want to do and go with it.
I will tell anyone anything that they want to know, (if I can) I just WONT tell how to do it, this is the business part of it, with 25+ years of experience, you tend to learn something both good and bad. The only way to learn is to make mistakes, then find out why so you don't go it again, or at least try not to.
BJR Racing
moper
Well-Known Member
Sorry guys, I've just been "touchey" lately..Do what you want, I do what works for me, and that's fine for everybody. I give opinions..Those are gotten by either experience or reference, sorry if that was a confusing deal..But I assume anything posted on the web is only opinion. There's no way to verify things here, unless sombody else says yes it works. In this case, it wont harm anything either way, it's a matter of taste really. Speaking of taste..It's time for breakfast!
Well, it seems like were all in this together, helping others. I agree to agree and disagree pleasently.
Good idea, the turkey didn't last in my stomach.
BJR Racing
Well-Known Member
Well I'm glad this is over, here is some info thats very useful to all. But keep this as a reference as these are for allout racing engines. Superflow states that the maximum valve size for a given bore on the intake is .52 X the bore size. Then on the exhaust you would X the intake valve by .72-.75. Thus the maximum size for a 318 with a 3.91 bore would be 2.03 and 1.52 respectively. But we all know that we don't have allout racing engines here so most cars are aprox. 20% less in efficentcy. So for the average bracket car this has to be reduced, without getting into a bunch of detail here these are the factors that I have come up with.
318-360 use 2.1
383-400 use 2.05
440 use 1.95
500-572 use 1.9
The idea here is to keep the port volume and the flow in a reasonable aspect, the #s that you will come up with here is the cc's of the port, then multiply by 1.6 for all mopar engine for the air flow.
Example: 318 divided by 2.1= 151 cc's this is very close to a stock 360 head volume which most are 150 cc's. Then multiply this by 1.6, 150X1.6=241.6 or 242 cfms this will get you in the ball park and satisfy most engines. Now this isn't to say that this is the most efficent head, thus if the port is smaller like the 318 heads with only a tiny 124 cc port then you also have to reduce the size of the valve for this to keep efficentcy up, it would look like this.
Example: 124 divided by 150=.826 or 83% of the bigger port, so now you have to reduce the valve size by 17% which is the difference between the two ports. This would look like this, 2.03x.17=.345, then subtract 2.03-.345=1.685 valve size to be efficent. Then the flow would also have to be reduced by the same amount which is like this. 242x.17=201 which is represents the heads from the factory.
Then if you have a mildly ported head thats 134cc's then the new valve size would be 1.807 for the intake and would need 215 cfms of air flow.
So with this we tried this out on a race car, and here are the results. The engine is a std. bore 318 with a .501 comp cams cam, a M-1 intake and a 750 vacume sec. carb, it also has 1 5/8 hedders and race mufflers it runs on 87 octane gas. The car weighs in at 3100lbs with the driver (70 Duster) The car ran a best with the 360 heads of 7.93 1/8 and now runs 7.68 1/8 with the smaller but more efficent heads with smaller valves. This is just some food for thought.
BJR Racing
318-360 use 2.1
383-400 use 2.05
440 use 1.95
500-572 use 1.9
The idea here is to keep the port volume and the flow in a reasonable aspect, the #s that you will come up with here is the cc's of the port, then multiply by 1.6 for all mopar engine for the air flow.
Example: 318 divided by 2.1= 151 cc's this is very close to a stock 360 head volume which most are 150 cc's. Then multiply this by 1.6, 150X1.6=241.6 or 242 cfms this will get you in the ball park and satisfy most engines. Now this isn't to say that this is the most efficent head, thus if the port is smaller like the 318 heads with only a tiny 124 cc port then you also have to reduce the size of the valve for this to keep efficentcy up, it would look like this.
Example: 124 divided by 150=.826 or 83% of the bigger port, so now you have to reduce the valve size by 17% which is the difference between the two ports. This would look like this, 2.03x.17=.345, then subtract 2.03-.345=1.685 valve size to be efficent. Then the flow would also have to be reduced by the same amount which is like this. 242x.17=201 which is represents the heads from the factory.
Then if you have a mildly ported head thats 134cc's then the new valve size would be 1.807 for the intake and would need 215 cfms of air flow.
So with this we tried this out on a race car, and here are the results. The engine is a std. bore 318 with a .501 comp cams cam, a M-1 intake and a 750 vacume sec. carb, it also has 1 5/8 hedders and race mufflers it runs on 87 octane gas. The car weighs in at 3100lbs with the driver (70 Duster) The car ran a best with the 360 heads of 7.93 1/8 and now runs 7.68 1/8 with the smaller but more efficent heads with smaller valves. This is just some food for thought.
BJR Racing
D-mailman
Well-Known Member
BJR, It was good talking to you on the phone today. You folks out there should listen to what BJ has to say. He is full of it...tech that is...LOL. Man surely knows his stuff. As do alot of the other members here too. I enjoy reading this board daily. Terry.
BJR Racing
Well-Known Member
Thanks for the kind words Terry......................I think.....................LOL. Good talking to you also, and looking forward to meeting up with you when you get here after the holidays.
BJR Racing
BJR Racing
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