I've got a chance to buy a set of ported and polished heads from a 82 Trans Am CFI (LU5). They have less than 1000 miles on them. The guy wants to get rid of them, so I think he'll sell the pair real cheap. I believe these are 416 castings. The heads are ported and polished with 2.02 intake/1.8 exhaust and three angle cuts. I'd like to use them on my 1991 RS L03, but from what I've gathered on this board, looks like these heads are for pre-87 305's. Can any confirm if these will or won't work on my 1991 305?

 

They will bolt up no issues as far as mounting to the block and accessories are concerned.

You will, however, need new valve covers as 416's are perimeter and yours are currently center bolt. For the same reason, you need new rocker arms as well. Also, the center 2 bolt holes on the intake will need elongating, which isn't hard.

*edit* are you SURE they have 1.8" exhaust? That's huge.

 

I dont think that 2.02 1.80 valves will work in that head. Simply because of the spacing of the valves. I am almost 100% sure that the valves would overlap. Most stock heads are this way.

 

You don't want 2.02 valves on a 305 anyway, to much valve shielding. You will not get correct flow around a poppet valve in such a small bore such as the 305. It will actually flow less than a smaller valve.

 

They guy told me the valves are 2.02 intake and 1.8 exhaust, but I think he was going by memory. I'll ask him to actually measure the valves.

I was planning on buying a set of World S/R Toruer 58cc heads and porting and polishing, but I got tempted to by these since they would be ready to go, except for the valve covers and rocker arms. I can probably buy the heads along with the engine (which has some other performance goodies) for $150.

 

One of the attractions of 14014416 castings is the smaller combustion chambers and reasonably sized port runners. Fitting 2.02 intakes and even 1.60 exhausts in those chambers would require either chamber modification that would enlarge them considerably to allow proper perimeter valve flow or enlargement for clearance only which would create a perimeter shrouding condition.

If the seller doesn't know what size valves are installed, I'm wondering if the heads are even in fact '416 or SBC heads. It's very easy to measure valve faces.

 

They surely arent 2.02 1.80 valves. If I could get the damned pics to resize I could show you a picture of 2.02 1.60 valves in a 305 head, and then you would know why you cant fit 2.02 1.80 in there.

 

1.8 exhaust valves can't be installed on a small block head because of the valve spacing. Its not possible to fit a valve that big in there, unless maybe you have a tiny little intake, like 1.72 or something.

The best size valves for a 305 block is 1.94/1.60 IMO... 2.02 is actually a restriction on a 305 because the edge of the valve is so close to the side of the bore/chamber that nothing can really flow past th valve on that side.

 

Exactly what I have been saying. I have 2.02 1.60's in mine, and it is as close as it can get. Of course they can be fitted into mall block heads, just not stock ones.

 

I am running 416 heads on my LO3 and after all of the crap with new valve covers and the center bolt hole thing, my advice to you would be to get some 081 casting. I would not do 416 heads again. But thats just me. I hate the always having to make do or re-engineer a piece to fit. Drives me crazy.

 

If you can wait a few months, I'll have a set of 081 castings with everything minus rocker arms and valvecovers (unless I buy new rockers and VCs). I've just begun to port the heads that are going on my motor... aluminum 643 castings (LT1)

 

Azvolfan, I agree with you. At first I was tempted to by these heads but the more I find out them the more I'm convinced to look for 081 heads or go with the World S/R's. Do it once and do it right!

 

DuronClocker, I'm not in a big hurry for new heads. Just got headers and cat back on, so I'm going to get started on prom tuning what I have first, then move on to more significant changes. If you're serious about moving your 081 heads, send me a PM with more info about them and $$. Thanks.

 

Seller confirmed he was going by memory on valve size. He's going to pull one of the heads off and measure the valve to confirm. I'm very doubtful they will be what he originally said.