Anytime - that is why I love this forum, everyone has great info or experience !!!

 

Why are their different type of GT40 Iron heads. I would like to get new heads, and this seems like a route id go. BUT, are all gt40 heads i see the same? why are theyre X303 and such heads? Are they different chamber size and whats reccomended? I also see GT40P? which would work on a stock 1971 302? Do these GT40P heads have larger valves? than stockers? im curious-Jon

 

theres the gt40's and the gt40P's - cast iron and aluminum. the P's are just improved in the port flow department - either set will bolt right on earlier 302's / 289's as long as you use the later model (78-up) rocker arms. i *think* pushrods are the same, but if they arent even new ones are very inexpensive.

if you have 800-1000 bucks go for the aluminum versions, if not grab a set of cast iron 40's or 40P's from a junk yard and have your local machine shop do a regular valve job. shouldnt cost more than 200 bucks for the valve job / resurface plus the cost of the heads.

 

My last head rebuild was $500. And that was just standard fare.

RHS makes some good heads. The original poster only has a Performer intake, so high flowing heads would be useless without a manifold change. I would suggest at least a Stealth intake (or Performer RPM) with a head swap. And keep the flow rate of the head complementary to the rpm the engine will see. No need having a head that can flow up to 10k rpm if the cam can only wok up to 5k...it will actually be a detriment to the performance of the engine.

A set of assembled heads can be had for $1k, a manifold would be just a couple hundred, and the rest should be spent on an engine balance, cam and valvtrain upgrades.

 

where the HECK do you live?

in central florida, at 4 different machine shops i have worked at the rate for V6 / V8 (non-overhead cam motors) valve job & surface is 150-200 and a camless 4cyl or straight 6 was 110-150 bucks.

you start talking about ohc V6's with the non-adjustable "hockey pucks" (think toyota 4 runner motors) and now your closer to 5 bills.

 

All new guides and seats andresurfacedintake/exhaust/block sides. Also had the machining done for screw in studs, but that's only about $50 and wasn't included in that $500 (I spent a total of $650...also resurfaced the valve cover seats, retapped the holes, and upgraded the valve spring seats).

 

i got my stock 289 heads redone with 1.85(intake)1.55(exhaust) put in along with a bowl blend and i did the porting b4 hand and they just cleaned it up plus i got manley stainless valves for 385 to be exact and i am waiting to fire up my motor eversince i got them back

 

colorado you think you went a bit overboard with all that resurfacing? btw we ran a tap down every bolt hole as part of the valve job anyways - not all shops do that though.

 

Nope. The surfaces were machined so everything was matched parallel and height adjusted to its mating counterpart. You'd be surprised how far off some of the surfaces were. They did look good by themselves, but weren't parallel to the mating component.

 

only time we ever had to machine intake side was if we angle cut the heads for the roundy round track. we built those damn SBC's so tight we'd break down running motors for some refreshing and the carbon on the heads has piston "kiss" marks on them. if only the boss we built wouldn't have grenaded =(

i wanna cry just thinkin about it