Opinions on heads please?

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Orionsax7

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Gonna be building a 450hp range 360 soon.

I currently have '71 360 J Heads with the 1.8"/1.6" valves(rebuilt about a year ago) on my 318.

What would be better to do? Buy some aftermarket heads like Edelbrock Performer RPM or Indy heads......or have these heads rebuilt for the larger valves? About how much would it cost to get them set for large valves and maybe a port job? If you can give me some typical price breakdowns that would be awesome. Thanks.

This will be a daily driver with 1/4 mile passes about once a month(maybe less) just for fun.

-Alex
 
Do not do any thing yet.Pick the cam you intend to use and from that you can determine the air flow needed to do the job.What type of rpm range do you wish to run,is it a street car with a few runs at the track to have fun,or do you wish to get serious.Its of no use spending 2000$ on heads if you only intend to use a .500 lift cam,or less and never push the motor over 5500rpm?If you can go into detail of what type of motor you wish to build,we can help you pick the right head,weather its a cast iron head ported,or a alley head,Mrmopartech
 
i really recomend the magnum r/t heads, they flow very well in stock form almost as good as a set of ported j or heads and ported flow almost as good as w2's for a lot less price.
you can buy them with the standard la intake pattern.
small chambers and big flow from .300 and up
iron or aluminum
$840 for the pair unassem. iron
or $1300 for alumn.

don't waste your time on 30 yr. old heads and spend more on machine work than the price a r/t magnum thats newly designed.

steve
 
It would cost me $800 plus porting to get a set of Js, or Xs, or other iron factory head to feed 450-500 horsepower. The fact they were recently done means nothing to the cost. New valves, guides, springs, retainers and locks all cost. The porting would cost you at least 3-400. Now, Edelbrocks cost $1300 IIRC, but that's out of the box. They wont run as well as they can with some careful attention to the valve job and setup. That's another 150 or so to get cleaned up. They would make enough to get 450 out of them at that point. More is possible with porting with the eddies. I'm not familiar with the Indys to make an informed judgement, but the BB Indy stuff is terrible in the valve job/seat ares. They will not make good power without work there, so I'd think the small block stuff sufferes the same way. If this is a street car, I would go Edelbrock for value and potential. If it were a race car, I'd go iron factory for less money, and better power potential with the iron chambers, and parts interchangability. W2s are a great choice for the race car too, but are in many cases locked into special intakes, headers, and valve gear.
I think it's safe to say the head budget needs to be at least $1700 to get a really good set of aftermarket heads, and at least $1200 to get a good but close-to-maxed-out factory set.
 
Moper is it really necessary to do a lot of port work to get 450HP? All the dyno tests I have seen of the 360/380HP crate motors have these engines easily reaching 420HP with just careful timing and jetting. They are built with magnum heads and 1.92/1.62 valves.

I would think a set of magnum heads (easily picked up for $300 or less) with a good multi angle valve job and bowl blending would support 450HP or a set of the magnum R/T's right out of the box would do it too.
 
As I said in my first post, this is a daily driver with 1/4 mile passes maybe once a month for fun.

What would it take to get a 360 to about 400-450hp? I was thinking maybe around .500 lift...maybe the mopar .508/.508 cam. Or do I not need that much cam to get to my desired hp range?

My first thought was getting a 360 short block rebuilt to about 10:1 and top it off with the Edelbrock Performer RPM top end kit(cam, lifters, heads, air gap intake, and a holley 750cfm double pumper). How much would this combo make? Or maybe the top end kit, but with a higher lift cam than the performer rpm?

What do y'all think?

I want to spend around $3000 or less on the entire rebuild. I have the '71 360 J heads to sell to help fund the project as well as a mopar small block performer intake and 650 cfm holley double pumper. All in great condition.
 
You wont want to use the .508" cam for a everyday driver. Its pretty big even though its not alot of lift. Duration at 050" is 248" wich wont work with power brakes. It also likes alot of compression at a ton of gear and converter.
 
DGC, my opinion is no, not without some serious port work on iron heads of any kind. The Magnums work great, but IMO, they are not the best choice here. The last 340 I did makes around 480 with Js on it. That's big valves, bowl work, cross section work, the whole deal. I did not flow them tho, so it's hard to say how good or bad they are empirically. I joke with my shop guys, that every set of heads I walk in with costs $800. It's not great, but to get the right results, the good machines demand good components. Any guide wear kills the seat quality, and that's 80% of the valve job's power right there. so now it's valves and guides..etc etc etc. In my experience, which is limited when talking about Magnums, these heads have consistently failed to perform on engines that were late model things, with blowers, and other stuff. Maybe it wasnt the heads, I dont know, but I wasnt impressed. I have been impressed by lower power engines running them tho. Under say 350 horse..Street engines. What I have seen is that it is very hard to improve on the stock Magnum port for low and mid range flow, and just as hard to get any higher lift flow and keep the great low lift numbers. It's still flowbench territory, because the tumble and swirl they create is easily trashed with a grinder. They are definately not my forte..lol On a side note, using any MP head should be approached in the same manner as Indy's...They are just as bad fit and finish wise, as Indy.
 
A lot of great info and I thank you all for it. I may be leaning closer to the Edelbrock RPMs but not 100% yet.

I guess the question I should ask is this:

If I gave you $3000, how would YOU make a 450hp streetable 360 without stroking? Just keep in mind that I already have '71 360 heads with small valves and a performer intake which you may either use in the build or sell for more money. And I will have to pay for any machine work since I don't own a place or "know a guy."

I could really use the help here guys. I'm looking forward to this build. Thanks.

-Alex
 
360,.030, stock crank/rods,good light weight piston 10.5:1(or as much as possible with pump gas),XE284H .507/.510(comp cams is having a sale on them).,your 360 heads with more work,AIRGAP (sell your intake), 750DP.

$3,000.00 and close to 450HP!!!!
just my 2 cents!!!
 
Mike, I'm impressed!..lol. I'd do just what Mike said, but a performance engine will use up that $3K quick. You'll need about $500 more to get a complete engine (you'd need a carb, headers, and ignition not included in the $3500). Not to change topics, but, exactly how fast do you want to run? 450 horsepower will get a properly equipped car into mid 11s. A car that is primarilly street doesnt really need that much, unless you want it. As power goes up, streetability goes down when your talking about factory sized small blocks. Power brakes wont function , and it wont idle well in gear with the cams you'll need for that power level. Not the best for a car that might race twice a year. Just a thought..
 
THANKS moper!!!!!....and i would have to agree with moper.....450HP to race twice a year is kind of OVERKILL....i figure im running around 425HP and ive gone 12.07@108 in street trim and not running to well...RIGHT MOPER??

i didnt included the carb,dist.,wires,headers,etc.,etc cuz it adds up QUICK!!!....but from the intake to pan $3000.00 is stretching it but could be done useing some GOOD used parts too.....like a oil pan,intake,carb,dist.headers.....thats how i built my 1st combo and im still doing it now!!! :supz:
 
Thanks so much for all your help. I'd like to break the 400hp range. And it will be a daily driver with track time about once a month. I just moved close to Baytown...the temptation is just too much. :) The racing will be strictly for fun though. This is what I got so far...

360 .030 over, stock crank/rods, Comp Cams XE274H-10 .488/.491, Edelbrock RPM heads and air gap intake w/ 750cfm holley.

Does this sound good so far? Will it break the 400 hp mark with 10.0:1 pistons? Which brand of pistons would be good for this combo? You mentioned light weight?

Oh by the way, the $3000 is for the engine only, I'm not taking into account ignition and exhaust. I already have that taken care of.

-Alex
 
DUDE!!!!!...your ALMOST there NOW!!! :supz: ...send the heads and airgap to RYAN JOHNSON @SHADYDELL SPEEDSHOP....hes the SB guru in head work!!!....he'll get you over 400hp with him porting those eddy's and airgap with your combo right now!!!...
you can also put on a PROFORM main body on your 750DP and try a carb spacer....as far as pistons theres a few to choose from..just look around for them on sale.

ROSS,PROBE,DIAMOND,WIESCO....mancini ALWAYS has them on sale!!

www.shadydellspeedshop.com
 
mikesduster said:
....as far as pistons theres a few to choose from..just look around for them on sale.

ROSS,PROBE,DIAMOND,WIESCO....mancini ALWAYS has them on sale!!

www.shadydellspeedshop.com
Click to expand...
Thanks for the info. I was looking at the KB741. I think they would have about 10.55:1 compression with the RPM 65cc chambers. What's the limit on compression for pump gas? Would you happen to know which kind of pistons would be good for my application for preferably not much more than $300? I was looking on the net but am not very knowledgable in the piston dept. Thanks

-Alex
 
I dont have my KB catalog handy, but I'll dig around a little later. As far as compression, with aluminum heads, I dont like to run anything less then 10:1. More towards 10.5. With careful planning, and good machining, you can creep that up to 11:1 or slightly higher and still run regular (91) unleaded. Go for a flat top design, and deck the block to have the pistons be at 0 deck height. Use the Felpro .039 gasket, and you have a good chamber design, so you can set the compression with the chamber size, and have good resistance to detonation.
 
moper said:
I dont have my KB catalog handy, but I'll dig around a little later. As far as compression, with aluminum heads, I dont like to run anything less then 10:1. More towards 10.5. With careful planning, and good machining, you can creep that up to 11:1 or slightly higher and still run regular (91) unleaded. Go for a flat top design, and deck the block to have the pistons be at 0 deck height. Use the Felpro .039 gasket, and you have a good chamber design, so you can set the compression with the chamber size, and have good resistance to detonation.
Click to expand...

Flat top design with valve reliefs or just flat top? With the Comp Cams XE274H-10 .488/.491, will they need valve reliefs?

I'm researching all this stuff on the net so I'm learning, I'm learning. Thanks again.

-Alex
 
By flat top, he means neither a dome or a dish... flat. Yes, you will need valve reliefs. But what you don't need is 4 valve reliefs like some of the TRW pistons have. Look for a compression height that will get you close to zero deck. That will keep you from having to mill the block excessively.
 
That was the other thing I was wondering... What is the 360's block height? I've been trying to find it on the net but haven't had any luck. I think once I know that, I'll pretty much be set to make my choice on pistons. Getting close now...
 
Use the KB107s, They are a flat top. Have the block milled so the pistons are zero decked. You'll have almost 11:1 compression with a 65cc chamber and the .039" gasket and it will run fine on pump gas.
 
Yeah Ryan is definately still in business. Good guy too. I went down to look at a 74 Dart Sport a friend of his had(if you look on his web site under customers cars its the yellow Dart Sport listed as total 340 rebuild) and Ryan was there too. Talked cars and SB's. I just saw him yesterday at Carlisle....or at least his heads and stuff in his space at Carlisle. I usually stop in to say Hi but he was either not there or away at the time I was there. He has some great looking stuff though and knows his SB stuff. When I rebuild my 340(not needed yet but when I do) as long as he is around thats where its going(and he lives within a hour of me so thats nice too). He built the sb 340 that was in the dart sport I drove(but did not buy) and that engine was pretty snappy(as in put your foot in it breat the tires loose snap your head back snappy :) )!
 
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