Prophe'c

Anyone know of the exact specifications from factory for the 1970 455 engine? Obviously there was more to the torque in the 4-4-2 than just the motor, however was considering on a build up of the 455 to eventually drop into a 1972. I read everywhere HP ratings could be over 400 but avg 320 and that the 1970 was the best year for the 455.

AZ455

I got this from my auto school Mitchell account, not sure of its accuracy or original information source.

Vega

I think it was 507Olds, not exactly sure, but i read just earlier today on here where a a member who builds Olds motors just finished a rebuild on a 100% stock 70' W-30 455 and it dynoed out to around 350hp/480tq (Net i think). I'll try to find the post...

Prophe'c

@AZ455 that helps! in fact, i know of a crate 455 puts out 370hp, drop in a torker by edelbrock and should be @ 400 so that may be best.

@Vega, thanks.

Vega

If budget permits id go with Edelbrocks, they flow better than any stock head, only the best come close to it, and theyre aluminum which saves weight, and they have lower CCs giving you a small boost in compression which will boost hp/tq. Not to mention if you have to get a set of stock heads rebuilt it might be more cost effective to go with E-brocks. That said its up to you though, im rebuilding my 455 with Ga heads because im very budget oriented and no matter how cost-effective it is, if i cant afford it i cant afford it haha

507OLDS

I could care less what the factory ratings were.It doesn't make that much power now.Are you as strong at age 60,as you were at age 20?Probably not.There is so much technology out there now,these rebuilt engines have no choice but to make more power than they did back then,with the latest camshaft designs,lightweight rotating parts,manifolds,heads,etc.
A stock 40yr old engine is a core,running or not.Just try to get one that is in good condition,and not blown-up or spun.

Run to Rund

x2. There is no big difference in performance among the A through GA heads. Edelbrocks will be better particularly if ported, but perhaps a more compelling reason is that their cost may be not much more than a complete rebuild of stock heads. I prefer the look and easy head gasket sealing of iron heads. Factory HP ratings were usually skewed for a variety of reasons including insurance costs if the weight/HP ratio got lower than 10 to 1. A W30 engine with a big cam might get rated the same or lower than a 88/98 engine with smaller valves and cam, for example.

The end result of your build will depend on cam, compression, heads, intake, etc. not on some unknown "magic" from the engine HP rating you started with.

Prophe'c

thanks for the insight Brian!... sounds like you put a few on the dyno...and helped me realize unless the vehicle is all original #'s matching with low miles (and certain it won't be), a 455 is going to be a 455 so the crate option is best. The decision to use either Edelbrock or some factory heads is up to discretion @ that time with obvious performance benefits etc of more modern technology.
awesome!

Oldshound67