if it ain't broke add more parts !

-
1

11.2

Well-Known Member
Joined
May 31, 2007
Messages
354
Reaction score
10
looking for some suggestions on sum upgrades to a 360. currently i have 9.5:1 compression, stock 1.88 heads with mild pocket porting, crane cam 278 intake .467 lift 290 exhaust .494 lift, performer intake, 750 mighty demon, mallory ignition box, 727 with 3000 stall and 3.91 gears. i do alot of street and seem to get at least 50 passes at the track.


i'm willing to spend around $2000 cdn so i was thinking of aluminum heads over the winter. just looking for some opinions on best bang for my buck.
are the heads the way to go or are my heads worth putting 202s in them and go rollorized? should i try finding a set of x heads? ect.
 
Well a little more cam will be nice with bigger valves or the aluminum heads. You also need more compression too especially with more cam. Out of the box the Edlebrocks run good and will raise compression with their smaller chamber. But that will eat most of the $2000.

Or for less money in the heads you could stuff 2.02s and 1.60s in the heads, mill them about .030-.040 and get a bigger stick to boot. You just need to make sure you match all the parts for the rpm range... IE power you run at. I think I would stay under.540 total lift and not to longer on duration for your combo.

The bigger vavles remember are only really gonna help in the upper ranges say 4k and up. You may notice less responce and power o nthe low end with more cam and gig valves, but some compression will help in this area some too.

Then once you are donce a good carb re-jet and distributor curve should do the trick. I would think you could get a real 50-80hp more and still be a godd driver.

PS the 915s with work are about as good as the X's The money gets spent fast on these heads when you get into port work, at that point unless you are a good do it your selfer, it is best to go with an aftermarket head for the $$ in most cases.
 
Fisrt thing I see is to ditch that Performer intake and get a M1 single plane or at least and RPM air-gap.....if you have the space under the hood. That intake is choking flow. Then have the 2.02's and 1.60's put in the heads and a bigger cam to take advantage of the new valve size.
 
are my heads worth spending the money on? i figured i would be better off spending money on some worthwhile heads such as x heads or aluminum.
what would it cost me to change these valves?
 
Are you running small valve J heads? If so yeah they are good heads especailly if you have the pistons that can get the CR up.
 
i'm not sure if they would be j's or not, i'll have to run the casting #, all i can tell you is they are off a 1978 block.
 
Smog heads....hmmmm. Hopefully some of the others here with more knowledge on Mopar heads will chime in here.
 
all 340/360 heads flow pretty much the same. The earlier 240 heads (68-71) had bigger 2.02 valves. Other then that they are all pretty much the same tll the 308 heads came out in the 80s. They have a better port or chamber I believe. The magnum heads that came out in 94 are the best of the factory small block heads.
 
here's a thought. if i want to change to a m1 or air gap anyway how about a set of magnum heads with some porting. i believe the intakes are different, is there anything else, pushrods perhaps?
 
Yep, they have pushrod oiling and rocker arms like the chevy setup. Magnum heads are by far the best iron head to work with. The heads on my mag 318 are mildly ported and flow 243 cfm@ .500" lift and 180 cfm@ .500" lift. Very impressive low lift numbers too.

Mopar sells a pushrod set for the conversion part # P5007477. sticking with that cam you could probably get away with stock non-adjustable rockers. Although you will be getting close to maximum lift allowed on the magnum head without trimming the valve guides back since the stockers have a 1.6 to 1 ratio. I'm assuming your lifters from the crane cam will have allowances for pushrod oiling.

I have those x heads, but pure bang for the buck, the mags are the best ticket in town. Have a friend with a set for sale. Just waiting to hear back from him to see if he still has them. Here's a link for the description. I can put you in touch with him if you are interested.
http://www.swordsite.com/sword/viewtopic.php?t=4492
 
i'm interested but i have a feeling by the time i do all the necessary changes i'm into a set of rpm aluminums.
 
I don't think you'll be into that much.

Here's pricing from Mancini US dollars

pushrods -- $40
stock replacement rockers -- $88
magnum airgap intake -- $290
lifters (if needed) -- around $90

Plus the heads at $300 CDN and say $100 in shipping

Assuming you are going to replace the intake regardless, for about $650 cdn you could do the swap including lifters.

The eddy heads at Mancini are $1360 US
 
and a set of valve covers and away i go.
what kind of shape are these heads in, have they had work done to them and when?
 
You can actually use the old LA style valve covers on the Magnum heads to help hide the conversion or just because you have them as well.
 
20 over speed pro f116p, what are ya thinkin
 
hmm....are those flat tops? Cast or forged? Are they zero decked or in the hole? I have a feeling with those pistons you are gonna get the biggest bang for the buck with the Magnum swap.
 
i've been checking around to a few machine shops and they all have the same response on the magnums '' if they are'nt cracked now they will be shortly''. i think i've heard this to many times from to many different people for this not to be true.
i think i'm down to 2 choices, aluminums or refit 202s and port my existing heads.
 
$2000 is a lot to spend. Edelbrock heads, RPM Air-gap intake, and 1 step up in cam while you have the heads and intake off. Just my 2 cents.
 
I have a set of eddy mag heads and they cost me $1700 CDN. The Eddy non mag were about $100 less. I think if you're not going the mag route, porting you existing heads would be the best bet.

The mag heads in question, I don't believe there has been any porting done. The mag heads tend to crack between the valves.
 
i checked out prices on cutting in 202s with mild porting. $1000.

$1600 gets me into aluminum.

i don't want to dump $1000 into a set of inferior heads, i figure spend the money and be done with it.

the only other thing i can think of doing is upgradeing cam, rockers and air gap for now and heads down the road but i'm sure i'll see better performance increase with heads.
 
I cant fid that number. 116 is the mopar 360 design, but they have an H series hypereutectic that's H116CP(020)f. That's a 2 valve releif floating pin flat top that is supposed to get 9.45:1 with 68cc. But it's not forged. Not a big deal, just pointing that out. If you have the assembly data that has head chamber cc and piston installed height, you can be more exact. Most guys dont. so...If you have the std head gaskets (.043 compressed, and the heads are really 68 cc, you have 9.5:1. If I had to guess, your pistons are in deeper, and the head chambers are a bit bigger, and the real compression is lower. Which is good. Going from a 68+cc head to a 61-63cc head will bump that squeeze up, and with the pistons that far away from the head (.020+.043=.063 for q eunch distance) and iron, you will need to cam the thing carefully to stay away from detonation issues. That's why i was curious what piston. If you simply slap on iron Magnum heads, it will be prone to detonate with a mild cam. If you slap on aluminums, you are better because of the AL, but you still have too wide a quench distance. 050 is about the max before thre is non or little effect. It's that effect that really raises the detonation threshhold. You could run a thinner head gasket like the MP, but that might put you over the limit again even with aluminum, with your existing cam. If you're aware of it, it's agood idea. BTW, many Magnum heads crack. Not all cracks will hurt performance at all. And, if you are buying a set anyway, and having them done, have unleaded hardened seats pressed in, and they wont visually crack. Or, simply buy a set of the Engine Quest heads and put them together.
 
His comp. ratio is low for a aluminum head and for the combo, overall, a straight iron magnum head & intake would be better.

Resell the intake and heads to fund magnum head work to handle the new lift.

current lift divided by 1.5, them multiply by 1.6 for the new lift.

Theres also milling and further porting of the head with intake upgrade.
 
You must log in or register to reply here.
-

Back
Top