motor for my 77 trans

[xdogmax]

ok been looking everywhere for motor to rebuild for my 77 trans am and found an ad in the classifieds today!! tell me if something is out of place or seams to be a bad deal please:

74' pontiac 400 big block, torn down, bored 60 over with 6x heads (heads have been ported three angle valve job with bronze valve guides shaved 100 thousands with ram air 4 springs motor comes with 2 cranks. 500 or better offer.

ok are the 6x heads any count?
is bored 60 over TOO MUCH?
and what is a three angle valve job?

[MagicRat]

Originally Posted by xdogmax

ok are the 6x heads any count?
is bored 60 over TOO MUCH?
and what is a three angle valve job?

6X heads are the correct factory original casting for a '77 with a 400.

They are pretty good.... for a late model smog head. The ports and valve sizes are acceptable for a stock or mildly modified engine. Their weakness is that they are a large chamber, low compression head.

Now, those heads have been shaved (decked) to increase compression. IMO the intake manifold should be port matched to ensure a perfect fit, since the shaving lowers the intake port height, relative to a stock engine

Note: if you are really going to slip in a wild cam and intake, a high performance aftermarket Pontiac head is better, but they are expensive.

A three - angle valve job is where the metal on both sides of the valve seat is machined to specific angles, relative to the seat itself. When done properly, this will slightly improve the airflow of the head past the valves, and will, (in theory) slightly improve power over that of a stock head. The concern here is if the guy who did the valve job really knows what he is doing and took the trouble to do the job right, so, IMO do not place a big dollar value on this feature.

All this head work is only as good as the guy who did the work. Porting, valve jobs etc must be done to a specific profile, for maximum results. Someone who simply enlarges the ports can ruin a head, instead of improving it.

As for the block....... 60 over is about the maximum bore you can do, without sleeving the bores.

IMO get the block thoroughly checked out by a machine shop before buying it, to make sure all work has been done properly. The block can be checked for cracks and core shift (resulting in excessively thin cylinder walls) after the boring. Check for alignment of all bearing saddles and for flatness on the decks.
Also the heads should be checked for flatness, cracks and leaks.

[MrPbody]

MagicRat covered a lot of well. The 6X heads are quite popular today, for the "strokers". The larger chamber makes a pump gas "friendly" 461 easy.

A "red flag" is the use of the term "three angle valve job". First, that's an abused and misunderstood term. It's what we do for STOCK engines. In olden times, it was considered "high performance". We learn... With the Pontiac, there's no "room" for the throat angle in the exhaust port without compromising the thickness of the seat itself.

Also, unless the porter was familiar with the quirks of the Pontiac, he may have "hurt" the heads, as MR pointed out. They are NOT Chevys, and must be approached from a different angle than the Chevy.

Agreed, a ".060" over block is done. Unless it's a real rare code ('69/'70 "WW" or something like that, it's not worth the expense of sleeving all 8 holes. Any 400 block from any "big" car, '75 or older, is a good block. 4-bolt mains or any of those other "buzz words" don't apply here. While there were a few made in Ram Air cars, no need for them.

Jim

[xdogmax]

thank you guys but at the last minute i went to craigslist.org and found a guy selling me a stock engine for 300 bucks and i researched the casting number on the block and it came from a 76 trans am!! its not 77 but im not splitting hairs lol just glad i got lucky!!