349 CI on the cheap

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BoredandStroked said:
Some questions from the curious youngester Bobby,

Did you put a race grind on the crank?

Yes I did put a race grind on the crank.


Did you lighten up the pistons any more then what they came as?

No as they are already lighter than the factory 360 pistons and there wasn't any need to do this.


What brand and style pistons did you use and how much did they weigh?

They were TRW forged pistons, and stock low compression, they weighed 609 grms and 154 grm pins.


Did you lighten up the rods?

No, as there wasn't any need to


Shave the heads any to get the bigger chamber sive shaved down to the 318s bore size?

No because the compression was already high enough.

Meant to say this earlier but if you did shave the heads it would increase the valve travel and start to hit the pistons so is there any way of putting deeper valve reliefs in the piston. I know this is boarderline crazy but just curious as always.

Yes I made the valve pockets .200 deeper for the cam that I used.

Thanks again Bobby for this post, I remember asking you about this type of engine but we didnt go into details.
Click to expand...

No problem.
 
Alright, but say the pistons wasnt sticking out above the deck due to the builder not needing to deck it much, and wanted around the same compression as you have, what would you reccomend?
 
Clint,
With this setup even without decking the piston is out of the deck .033. You would have to cut the heads a good bit to get the same compression ratio.
 
HOLY JESUS!!! thats a whole bunch of power, and not just a 318, any small block. i think i have finally found a purpose for my standard '68 318. great thread BJR, opened my eyes to a whole new approach
 
I want you to know I believe this is a very good thread.....But I have some issues with it...You are claiming to get over 600 hp on a flat tappet cam...(maybe a roller. not a flat tappet)....Because this would have to be tire horsepower to do what you are claiming...This would be 1.71 hp per cu. in...I do not believe this can be done with the combination you are describing...If it dyno HP, then you would only aprox. make 480 hp to the tire, which is not a 9.90 it would be a 10.10 if e.t. and mph was on top of each other...This is possible, but I don't think on a small flat tappet...We have tried alcohol injection, hats, and alcohol carbs...Never got a full second out of a fast car...Maybe a slower car...Kinda like 100 hp of nitrous on a 13.00 car..could p/u to 11.80 - 12.00's....But put the same 100 hp on a 9.90 car this will only make approx. 9.40 - 9.50... The computer always says an 1 5/8 header will work better on a stock type head...I have tried it, it's not true..Maybe a chebby, but not a mopar...A mopar has to breathe...The 360 head will not flow enough...Might look into some edelbrocks...I hope it works for you...I will play with it my computer program and see what it says...It is always pretty accurate...I am planning on building one of these also, just with a little different combination....I'm just hoping mine starts when I am done with it ...LOL... I hope in no way you think I am being detremental or mean anything bad with what I have said...I am 39 yrs. old and have been around drag racing all my life and I just don't think this will happen with the combination you have described....Lee
 
Lee,
No offense taken.
I respect your opinion, I too have been around drag racing all my life, I'm 48 years old. But I have already taken a car that was running 5.50 in the 1/8 and with adjustments to the alcohol injection turned a 4.97 and this was just in tuning. And no other changes.
I believe that this engine will get me to where I need to be as my .040 318 with 302 heads has already run 7.303 @ 96 mph with a 1.53 60 ft. time and this is what that engine has in it.

M-1 intake
650 dbl pumper race carb
302/318 heads gasket matched and bowl blended
1.78/1.50 valves.
stock pistons,rods and crank
.480/280 hyd. cam
1 5/8 hedders
87 octane gas
timing set @ 30* total
iron adjustable rockers and chrome moly pushrods
valve springs with 110 on the seat and 310 open

Now this engine makes 316 HP to the tires and even though your calc. comes to 480 @ the tires then 164 more HP to the tires should get me there. According to my calc. that I should run a 9.96 or 6.33 1/8.
But once again and were getting off point here that this is suppose to be a engine that can be built on the cheap and give reasonable results even on pump gas. The hedders were choosen for street use and mild racing, and the ease in hooking up the exhaust. Not because they made the most HP or tq.
 
Billy, I think he's confusing 1/4 mile and 1/8 mile ETs. I've seena few strong "claimer" type engines, so I'm not debating whether you can do it. Just whether it's doable for a general guy. I have seen factory blocks off more than .028" on the same deck surface, and more than .015" from the outside to the inside edges on tha same deck...lol. So your figure of .033 is perfect in a "worst case" scenario. The head milling is up to the builder, and again why I would say it's not easy to duplicate. There are a few things I wouldnt do, but that's what makes the world interesting. I want to look into that 283 piston idea...but I wont see a couple piston books until Saturday...lol.
 
Moper,
This is good and I would like to see how you would go about doing this engine with your ideas and parts, but @ 349 CI and be able to keep the cost down.
 
No, I am not confusing 1/8 mi. and 1/4 mile times at all. I am not for sure about the 6.30 being a 9.90( he is probably right) but, I do know a 6.40 is a 9.99. The 7.30 he is stating that he has run is approx. a 11.20 to 11.50..Sounds a little high geared for he is running more mph than the car is et'ing. This is what I was talking about on gettin your #'s on top of one another. When you have everything tuned and geared to it's maximum performance you et will match mph...This is a good thread and I do believe the 349 is capable...Moper, you are right on the 283 piston...I believe it was keith black that I found it...I believe it was one of there silvolite cast pistons though...Alright, for a non high winder (street cruiser)...Here are the spec's...LOL...Found my scribbling...3.875 bore....1.66 ch.....927 pin w/ a chebby rod
Another one is Part# 1278...3.910 bore...1.658 ch.....984 pin...chrysler rod....You guys look at these and see if my calculations are right...Thanks, Lee
 
My 360 will have to be taken out to at least .030, but this .040 with 340 pistons really got my attention. I have a 1977 360, will my block tolerate an .040 bore? I have been told that they have thin castings. I don't want to mess it up!
 
AdamR said:
You can buy a Mopar Perf crank with a 360 stroke and 340/360 mains for about $350
Click to expand...

But you can buy an Ohio cast 4" stroker for $299. If you have to buy pistons anyway why not go with the cubic inches.

Just something to think about. Certainly if you are bucks down and just happen to have this stuff laying around, by all means, have fun. But if you have to buy some or most of this stuff, go with the cubes.

Just to add a little fodder, I really liked my 3.31 stroke engine, That thing really sang on the top end. My 3.58 stroke engine still gets the job done but it's not the same on the big end.
 
Guitar Jones said:
But you can buy an Ohio cast 4" stroker for $299. If you have to buy pistons anyway why not go with the cubic inches.

Just something to think about. Certainly if you are bucks down and just happen to have this stuff laying around, by all means, have fun. But if you have to buy some or most of this stuff, go with the cubes.

Just to add a little fodder, I really liked my 3.31 stroke engine, That thing really sang on the top end. My 3.58 stroke engine still gets the job done but it's not the same on the big end.
Click to expand...

High RPMs and stroker cranks need a little more work than just bolting together a few off the shelf parts. You have to add more air flow and not just for the added CI but you also have to factor in piston speed. As piston speed goes up the time to fill the cylinder goes down. I did not factor this in 10 years ago when I built my first storker motor and I had to pull the heads and port to wake it up.
 
You can bolt anythign on a 4" arm engine, but you are right. The heads and intake begin to choke them very quickly. Meanign low rpm. But the 3.58 arm is a 360 base. They are fed fine with std heads, assuming the combos are properly built. 318 and 340s are very similar. 360s are able to be cammed and headed a little differently. If you dont, you get a power band that tapers off earlier than what might be expected.
 
OK, I'm lost here, and I mean no offense to anybody, but why spend extra to give up displacement. Sure BJR's combo should work, but if I had a 318 and 360 core motor sitting on my shop floor, I would be inclined to use the 360 block and put the money saved from weakening the crank towards some good pistons which would last longer at this power level. I guess I would have to find some other way to give up the 11 cubic inches. And then there's the issue of ending up with a 350. If I wanted to have a 350...
 
I think it's one of those... just to say you did it ont he cheap... deals. No harm in playing around with ideas...lol. Plus I just picked up a 318 Magnum shortblock and a 360 Magnum longblock Saturday... I didnt get to see the catalogs tho...
 
You have to give credit to BJR to come up with a new combo that is cheap and makes good Horse Power. Nice to see someone thinking and leading and not just following.
 
I'm not sure where my post went. i wrote it a while ago, it lokoed like it went up...Anyway..

I finally got to the book I wanted. What I would do is go with a flat top 307 Chevy piston, .040 over. Specs end up like this: 3.935 bore, 3.58 stroke, 6.123 rod, yeilds .015 down in the hole on a 9.6 deck. I have found dished and flat tops w/4 valve releifs in the few tries at searching. $122 plus shipping w/rings off ebag. The pistons would need the pin bores cut for pin retainers. Most blocks are taller than 9.6 to start, but it gives a little wiggle room if needed. The valve releifs are not placed right, but I think running them .015 down, and runnnign Magnum or 302 type heads with a mild to medium cam would make things fine anyway. The rods would need the bushings swapped to ge tthe chevy pin size of .927 from mopar's .984. But that's no big deal, part of re-doing rods anyway. All totalled, it would end up aounr $1300 plus parts, for bore, hone, sq deck, redo rods, modify pistons, turn crank, and balance. I'm sure the complete engine could be done for under $2500 using swap meet or ebag stuff, and buying a set of new/done Magnums. Assembling yourself too. That makes a 10ish:1 static 348 with good qeunch, modern heads, and decent street manners. It would be decent for mild truck or street/cruiser. Redline would be 5500. That's how I'd do it. I had a 318 with some chevy pistons years ago, and they worked fine.
 
Yes sir Moper,
Now you are talking a cheap build for the common street guy. I don't understand why the red line would be 5500 though...Can you explain...We have twisted these 360 cranks in the upper 7000 range without a problem or would it be based on the mains being turned down...Maybe the cam you picked out?...Anyway, would like to hear your input...Thanks, Lee
 
318 pistons are around $80.00 and rings are another $30.00 or so and you wouldn't have to change the size of the rods on the small end. Which is as cheap as the chevy stuff. The thing that I like about the hyper's is that they have the valve reliefs already in them and placement is right. I may shelf the cast ones and use the hypers. They may be a bit more but should be worth it.
 
My concern is more for the compression height. Adding that .135" in most blocks means popping out, like what you mentioned. I know you can take some off cast or forged pistons, but milling the entire top of a Hyper puts those rings even higher. 70, my feelings about the strength of the crank turned way down, and the cast pistons makes me set that limit. I tend to be conservative in that type of thing because it suits me better. Plus, in reality, most guys are not racing the engines much higher than that unless they know little about torque peaks or run 4.30 or lower gearing..lol..

BJR, do you know any shorter (compressionj heights in the 1.65 range) 318 part numbers? I cant find much. But there has to be somkething. Maybe a marine or agricultural piston number...
 
Positive deck pistons are of no issue if you have the clearance. Some 273 and 340's are positive deck motors. If it was to be a problem you can run a thicker head gasket, say a .060 gasket and now it is of no issue. Sure the rings will be farther up in the bores but that isn't an issue either being it isn't much higher and the chamfer in the bores is quite small.

Your 307 piston thing is interesting though.


Chuck
 
Moper,
I found a piston from Sterling and it has a 1.658 compression distance and the part # is LC371P, it comes in std, 20, 30, 40, and 60. It fits 67-84 truck with .040 recessed head, designed for pressed or floating pins and states that it's 7.0:1 rings are 2 @ 5/64 and 1 @ 3/16.
With this piston and the block machined the way that I did mine I would be .001 below deck with .030 off the deck, so now a .038 gasket and a 302 head would give preferred quench and near 10:1 compression.
The other way I was thinking was that I would use the 360 head with the open chamber and let the piston stick out and create quench with the piston and the thinner gaskets. But the engine could be built either way.
 
Moper

This is true, but your peak torque is gonna depend on the cam you use...Not everyone will use the same cam and I do run a 486 pro gear... or are you just basing this off the small flat tappett that you guys were first talking about...Because I would not use that cam myself.
 
BJR...A larger flat tappet ! Try thes and see what they say...I cannot get my program to run...Will work on it though..LOL there are 3 cams....
Cam 1: @ 50 Int...242---543>>>> Exh...248---563 ... 107

Cam 2: @ 50 Int...237---534>>>> Exh...242---543 ...107

Cam 3: @ 50 275 >>>> 585 Straight across 108
 
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