About a month ago I picked up a rebuilt to stock (big dish pistons) 1972 Ga heads 455 ($500). Now I found a stock rebuilt 69 olds 455 C heads bored .30 over and .30 over on the crank ($400) dissasembled but rebuilt. Is there any difference between these motors other than the pistons & maybe cam? If it's worth it I would buy the 69 and sell my 72. My 72 has the 2.0 intake valves. Or is there a few things I can do to make my 72 block the same? My car is being used for a weekend performance street car. The guy is also willing to part the motor out since it's rebuilt but not assembled.

 

I assume you mean .030 rather than .30 . Well if that apart-but-rebuilt '69 455 has higher compression pistons and 2.07 intake valves, then go with the '69 and sell the '72 since you said the '72 455 was already rebuilt to '72 stock with "big dish" (i.e. low compression) pistons. You're just not gonna get a whole lotta "weekend performance" from what is probably an 8:1 motor (ask me how i know ).

 

If the '69 is all apart, you can finish the machine work and up the compression and have a better performance engine. For a hot street car the the 2.00 valve compared to the 2.07 valve, you would never see or feel the difference.
You best bang for the buck is raise the compression, degree the cam, adjustable rockers, headers(shorty or long) "HEI" dist, performance balance job and a great carb.

Gene

PM me if you want more info.

 

That 69 455 is not rebuilt if it is not assembled,but it sounds like he had a lot of the machine work done already.I would keep your 72 455 for now.Get the 69 finished & assembled,before you sell your 72 455.Does the 69 455 have cast or forged pistons,and what other parts are included?

 

The 69 455 the block has been machined .030 over, and comes with new pistons for the over bore, cam, intake, new oil pan, new timing cover, timing assembly, heads, and carb. The seller doesn't give any brand names or specs of the parts. I just called him and he sent me a picture of the pistons and they seem to have a big dish too, but not as big as my piston dish. He also said the heads are A heads so I passed that deal up and will just rebuild my block. I didn't even know A heads would fit a 455 maybe he has a 400?

The 72 455 in my garage is on the engine stand with the heads and oil pan removed. It was a running motor when I bought it but the seller didn't have any history on the motor other then he wanted to swap it for a Ford motor since it was in a Ford f100 that he picked up from a auction. I bought the complete motor turnkey ready, all accessories, stareter, a/c, belts etc still attached. I payed core price because I had no idea what the motor looked like on the inside. When I removed the oil pan the motor looked like a low mile rebuild. Everything was so clean and new looking. No sludge or oil residue build up anywhere. The cylinders still have the cross hatch and are not out of round. You can barely feel the piston ridge. I used a telescoping gauge and caliper to measure the cylinder bore from different angles and it's very close to 104.8 mm. The piston to deck was close .032 with a feeler gauge. With the 40cc dish pistons my compression is about 8.1 and with fel pro gaskets 7.87:1 according to the summit calculator. What should I do to this motor you guys think? I was going to CC the heads when I go home today and if they are stock 80cc I'll by the 15cc dish pistons and it should have me around 9.42 : 1 with felpro gaskets. I'll add on a performer or air gap intake, 750 cfm carb, headers, hei, maybe bigger valves if recommended. Then I'll need help with cam choice if anyone can recomend one.

Bore 4.125 inch
Stroke 4.250 inch
Head volume 80cc
Piston Dish 15 cc
Deck .032
Compressed gasket .039
V8 455

Compression Ratio : 9.42 : 1Total Displacement (in.3) : 454.38Total Displacement cc's : 7448.85
Howcome summit calculator says I got a 454??

 

Yet another example of how Chevy is trying to take over the world!

Actually, the calculator is right. Olds Marketing (or Engineering?) decided to round it up to 455. Seems unlikely that they actually thought this would sell more cars, so it was probably just to differentiate themselves from Chevy.

For what it's worth, in later years the Chevy "396" actually displaced over 400 cubes. But they wanted to keep calling it a 396 because of all the marketing they had invested in it.

 

Then they made the 402" because they didn't want the big 396 to have less cubes than the small 400.

As for your 72 455,it sounds like it has stock deck height,with the pistons sitting .032" in the hole.You could take .010" off the deck,to help boost compression,and also insure a flat gasket surface.Check the deck height on both sides of the block.You may find that you need to take more off one side to square everything up.

 

Im doing an ironicly similar build. 72' 455, stock bore with Ga heads and i just picked up a set of 69' 15cc pistons for it to boost compression. Just like yours mine is going to be a rather stock-ish build with as much "at home hotrodding" thrown in to scrape up what extra performance i can without spending an arm and a leg on aftermarket parts. Im aiming for at least 10:1 CR but idk if i will hit that, i'll have to get some milled off the heads and if that costs too much i'll take the hit on CR to save on the wallet. I'll definatly be following this thread closely as it closely resembles my build. So far ive got most of what i need down and am looking for a decent cam choice. Im looking into Lunati VooDoo cams around 270-280 or so. I know, lots of cam, but i'm looking to run a 4-speed and the last thing i want is a tame or even mild idle (i know these motors can handle a lot of cam, one guy said he was running a Comp xe274 and it was "mild", but i also think he was running an auto transmission) Im wouldnt cry over a slight loss in torque, these motors have waayy more than enough to spare anyway haha

Just for refference, isnt the Olds 455 older than the Chevy 454? Just thinking of the whole "i think they called it 455 just to differenciate from Chevy" thought

 

Vega,
measure the bore of the '72 block and measure the '69 piston at the skirt and the difference will be the piston to cyl wall clearance. Be careful with cast pistons as to much clearance is not good for cast.
Also the closer the piston is to the top of the block, the better off you are, and the "CC's" in the head you need to know. The closer to the top of the block gives you better squish in the chamber. Low compression and big cam will be doggy.

Gene

 

Thanks! Will definatly keep this in mind. Dont mean to hijack the thread though haha.