Im starting to build a stroker motor out of a 94 5.8 for my 74 Bronco.I keep seeing these cheap heads on ebay and im wondering if anybody has tried a set?How well did they hold up?

I have another question.These adds say 351 and 302 heads are the same fit but I was always told they were different.Do they machine them different than stock so they will fit either or do I need an adaptor?


http://cgi.ebay.com/ebaymotors/ProCo...item563d8f68ce




Thanks Trash

 

The only difference is the holes for the head bolts, when I put gt40's from a 302 on my 351 I had to drill them out

 

These Procomp heads aren't the worst heads you can buy but they aren't the greatest either, 3rd party feedback suggests they will outperform the World Sr's but fall a bit short of comparable heads from AFR or TFS, so as usual you pretty much get what you pay for. That's the performance side but unfortunately that often extends to the build quality and durability side too, to get more feedback on that maybe post your question on one of the Mustang sites where they typically have more experience with aftermarket heads.

 

me and my cousin both had a pair of pro comps (part # 3036C).. i did a little (very little) port work and gasket matching and my motor outran his with a junk intake and small cam, compared to his blueprinted cam, big intake and high compression pistons(among other goodies)..

basically, what i'm trying to say is.. with a little port work and gasket matching, you can't beat them for the price. a monkey can do the port work i did with mine.. same goes for the gasket matching..


the link you posted is actually a better version of what i had.. mine only had cast valves or whatever the older versions had.. i ran mine for about 23,XXX miles and they never gave me a problem.. the bottom end was a different story.. lol

 

What is this "Gasket Matching"??? I've never heard of this.... No I don't live in a cave either LOL!!!

Circled-Mistake Racin

 

gasket matching is just opening the ports up on your intake and heads to match the port holes in the gaskets..

best and easiest way to do that is take your old head gaskets, bolt down your heads, clean your old intake gaskets of any oil deposits or silicone, spray paint them, put them in place and bolt your intake on.. wait a few minutes so the paint can dry a little, then disassemble(before the paint dries completely, because the gaskets will then stick to the intake and head, leaving a bigger mess to clean up).. the paint on the intake and head plane will give you an idea of how far to open the ports up because the paint will only cover the contact surfaces of the gaskets.. then break out the dremel or air grinder and go to town.. once you're done, clean the surfaces of the paint, flush the heads and intake out to clear all the aluminum fragments and start putting everything back together

 

Are their gains in Any motor??? Will I see noticeable gains in my 1988 5.0 302 non MAF???

 

it's not a huge gain, but a significant gain, especially if you're planning on running a bigger cam and what not.. it improves air/fuel flow

and yes, it works on every motor

 

Pro Comp = meh. Spend an extra $200 for some made-in-the-USA FRPP X303 heads.

Gasket matching may or may not help. On the intake side the manifold usually has smaller ports than the heads, so hogging out the ports on the heads will only make it worse. The port floor and short side radius is where work usually needs to be done, but you can make it worse if you don't know what you're doing. On the exhaust side, opening up the bottom of the port is a waste of time. If anything, just unshroud the valves a bit and knock down any obvious casting flash. There will be plenty of casting flash to knock down on Pro Comp heads...

 

that's why you do the same with the intake.. gasket matched pro comps and a ported/matched victor jr are an amazing combo with a big cam like my blue racer..

as for the casting flash, 9 times out of 10 the pro comps you buy off ebay are already cleared of any flash

 

Gaskets are made to accommodate a wide variety of intake/head combos - i.e. the opening is usually bigger than the ports because there's a lot of variance from intake to intake, etc. and gasket makers want to sell a single one-size-fits-all part. There's nothing magic, or even relevant, about the port size on a gasket for a given combo. It's just convenient to use the gasket as a template vs. all the measuring and scribing it takes to accurately match the ports to each other.

So what you've done is create a "bubble" in the middle of the intake bigger than the port on either side. Which creates turbulence. It's better to just blend the manifold back a couple of inches to match the intake ports on the head.

Of course, it's basically irrelevant unless you're seriously into racing anyway. All that matters is you're happy with your combo. FWIW though, you could pick up another 50-75hp minimum with an out-of-the-box set of CNC ported AFR heads.

My two cents, YMMV.

 

i should have been more specific lol.. i didn't mean taper the port openings to create a 'bubble'