Justin79350

Hey guys i have a 79 camaro z28 wit a 350 and i have some powerpack heads i never heard...........if u guys could help me out and tell me if they are good or not it'd be greatly appreciated
Thanks

8Mike9

Man, that's an old term...used back in the late 50's and early 60's...the "Powerpack" heads were on the 4bbl versions of the 265's and 283's...I don';t know all the ins and outs, but probably had smaller combustion chambers to increase CR, and larger ports than the 2bbl version engines.

Either way, they're not reall what you'd want in todays engines...

I'd run the casting numbers at www.mortec.com, see what they came from, some guys will spend some $$ on them for restoration purpose's.

ede

they'd be small valves and small chambers. there would be a chance of the valves hitting the deck surface since the 283 bore was 3.78 or something like that. the heads wouldn't have holes for accessories and would need reworked. they wouldn't flow very well and would cost a fair amount just to make them servicable.

RB83L69

That's what people used to call the old "fuelie" heads, the first double-hump castings from the early 60s. People who don't know what they're talking about are usually the ones who use it.

Anybody selling heads that calls them that, more than llikely, doesn't have any idea what heads he actually has, or what the term refers to. Ignore it as pure BS.

If they're the original double-hump heads, they were the best there were in their day, but that day is long gone. They won't have the late-model (69-up) accessory bolt holes that these cars require if you want to include such conveniences as an alternator. There are double-hump heads that do have the bolt holes, but those are much harder to find, for some odd reason.

Get the casting number, see if they're something decent, don't believe the BS without verifying it some other way.

Here's the "double-hump" casting mark, on a set with bolt holes.

ede

rb jump in here and correct me if i'm wrong but i was thinking powerpac heads were from 283s, 2x4 283s and FI 283s from the late 50s and very early 60s. casting mark was a triangle on top of a rectangle.

8Mike9

It could be one of those "mis-used" terms, depending on what circle you run in. Kinda like those who refer to all double hump heads as "fuelies".

In fact I just did a search Google, and came across a site referring to '69-'71 heads as "Powerpacks". Never heard of that era referred to as the same.

RB83L69

ede, I'm not really sure which ones were called that first. You could easily be right. The ones I have mostly heard referred to that way were the 63-up 327 heads on Vettes with FI. Wouldn't surprise me though if that wasn't the original usage, these things have a way of taking on a life of their own.

That's one reason for avoiding the term.... nobody knows exactly what it means. Nowadays it's kind of like the infamous "¾ race" cam. Just what cam is that anyway?

Definitely a mis-used term, no matter what.

ME Leigh

Yeah i believe that the original "power-packs heads came from the late 50's early 60's and came on 283. If this is what you have sell the to a restorer, never use them they will most likely be trash.