Team Chevelle banner

Power pack vs 305 heads

20K views 16 replies 6 participants last post by  BillsCamino 
#1 ·
Looking to redo my '65 SS 283-- Is it worth it to redo the power packs with a 1.94 intake valve or is it simpler (and cheaper) to get a nice set of rebuilt 305 heads- Always wanted the darn bolt holes anyway- Besides nostalgia, is there any reason to keep the originals after some machine work? One looks like it's not original but from the same era. Are they worth much to sell?

Thanks, folks-
 
#2 ·
If interested I've got a couple sets of fresh -601 305HO heads available and can sell for cheap.
HO heads will raise the CR slightly...chambers run from around 55 to 59cc and offer hardened seats. Along with accessory holes as you mentioned.
The ones I have been upgraded with springs, guide plates, and screwed in studs.
 
#3 ·
Thanks- If you could get me a message with terms? But I'd like to see if there's anybody with an argument for machining the old school powerpacks? Are they worth it?
 
G
#5 ·
Real PP heads intake ports cc in around 137 cc's whereas the earlier, sparkplug trough heads like the -306's came in right at 120 cc'! This is what turned the PP engine on, imho!

My set of 305HO, -601's cc at 160.0 and 160.+ cc's so are quite a bit bigger than the PP heads!

They also chamber cc'd at 53 and 55 cc's so you really have to cc them.

I figure a slight cut down on the -601's to 50 cc's and shim headgaskets will be great for a 283/292 engine! Please run the CR numbers tho here to be sure for both the .015" and the .020" thick shims... And I'd use a piston DITH of the stock .025" here.

Add a 2101 Performer or a Weiand 8004 and even the "top-dawg" Holley 300-36 intake and a 500 to a 600 cfm carb, a Duntov -097 cam or a CC 270S/Isky Z-20/the little Crower solid lifter cam and a cheap set of headers and go have more fun than John Law will allow as long as you have any sort of decently geared drive train at all!

Old-school all the way!!

pdq67

PS., about forgot, a cheap set of at least Z-28 springs, (aka, -142)..

Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
 
#6 ·
Thanks for the good advice----- Would a larger intake valve be possible in the power pack head? recommended? Expensive? Those 305HO heads are matched pretty well to the 283 it seems and not expensive- The double humps on my 327 are fantastic but the CR might go down too much if I swap them to the 283.
 
#7 ·
One more question- Is there a market for power packs if I sell them and would double humps; 1.94 intake and 64cc, be OK for a 283? Compression get too low, maybe with an RV cam? Many thanks---
 
#9 ·
i have never heard of power pack heads.What year and type of car were they on?
 
#10 ·
John, never seen them still in the car, but they are the 283 heads with the triangle casting on top of the rectangularish casting that is on the ends of all 283 heads.

Do the 1.94/1.50 valves in camel humps clear the 283's smaller bore?

as for lower compression ration, just use pistions to make up the difference.
 
G
#11 ·
John,

How old are you? B/c a PP 283 was the upgrade from say 185/195hp to 220 hp way back then by the installation of the bigger intake ported PP heads, a WCFB 4-barrel carb and real dual exhausts!

PP 283 sucker's ran way better they should have back then and I know. Add a great old Duntov -097 solid lifter cam and have more fun than John Law would allow back then...

And even a step WAY up to the old 30-30 fuelie solid lifter cam turned them WAY loose up top!!!!!!!

And again...

"Real PP heads intake ports cc in around 137 cc's whereas the earlier, sparkplug trough heads like the -306's came in right at 120 cc'! This is what turned the PP engine on, imho!

My set of 305HO, -601's cc at 160.0 and 160.+ cc's so are quite a bit bigger than the PP heads!

They also chamber cc'd at 53 and 55 cc's so you really have to cc them.

I figure a slight cut down on the -601's to 50 cc's and shim headgaskets will be great for a 283/292 engine! Please run the CR numbers tho here to be sure for both the .015" and the .020" thick shims... And I'd use a piston DITH of the stock .025" here.

Add a 2101 Performer or a Weiand 8004 and even the "top-dawg" Holley 300-36 intake and a 500 to a 600 cfm carb, a Duntov -097 cam or a CC 270S/Isky Z-20/the little Crower solid lifter cam and a cheap set of headers and go have more fun than John Law will allow as long as you have any sort of decently geared drive train at all!

Old-school all the way!!"

And I'm talking GOOD HP here outta the little motor up top!!!!!!!

B/c a hopped up 265/272/283/292/301/306 can make at least 500 hp "balls-out" and can be shifted at 10,000+ rpm..............................

pdq67

PS., about forgot, a cheap set of at least Z-28 springs, (aka, -142)..

Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
 
#12 ·
Darn right, Mr. Old School! When John wrote and asked what power pack heads were I just stared at the screen! (my '65 is three years older than I am, by the way). But hey, in this day of well built, CHEAP crate engines and ebay, etc., it's hard to justify all the machining and modifying of the stuff that you have sitting around in our garage- that's why I asked 'power pack vs 305' in the 1st place... In my SS was the mostly original 283 with the 2 barrel making 190 or so horsepower. Bought it in 2001. In 2003 I bought a junkyard 327 with the double humps and rebuilt the whole thing, did it right, am driving it since--- Cost me a bundle! Now it .060 over, the heads set for unleaded. It's not all old school, though- I have an edelbrock intake and carb, electronic ignititon, new headers...... BUT- the 283 stares at me on the cradle when I go into my garage, and this is my hobby for crying out loud! So I wonder as I drive away with my perfectly good motor, just like I did when I took out the perfectly good 283 6 years ago, what can I do to rebuild that and get a couple of more ponies, really rev the crap out of it, and feel -a little- better when high test is $4.50 again! SO----
1) Put bigger intake valves in the power packs
2) (by far the cheapest way...) swap the double humps over (the 1.94 valves clear, but I'll triple check along with the drop in CR)
---OR---
3) get a good, cheap, reman. set of 305HO's with the bolt holes and know they are good to go for probably way longer than I have the patience to leave them in before I get itchy for another project..... (Like putting the damn 327 back in because more cubes is the American way.....)
Does John want to buy the power packs that most probably need an expensive trip to the shop for $50 and $1,000 shipping? Cast iron is soooo heavy! Thanks guys, you are keeping me laughing this morning!
 
#13 ·
I am 39 and ironically I just saw a set of power pack heads for sale at swap meet yesterday,so now I know,thanks to you old guys!!:beers:
 
#14 ·
heh, listen to the old guys, they know a lot. I'm only 30 but I learned a heck of a lot hanging out with the old school guys from the machine shop. Thats how I know about things like power pack heads, and using a 283 crank to make a 302 out of a small journal 327.
 
G
#15 ·
Fwiw, Chevy used 1.94"/1.50", -461x, small chambered double hump, heads on the 290 and 315hp /283 engines just before the 327 became King.

The 283 I finally got that my Airhead Nephew once owned has a good set of -291, big valve heads on it. It came w/ a TRW TP-146 spec'd at 308/246, 108/106.5, .429" lift hy-cam.

It has flat-top pistons and I figure .039" thick blue composite overhaul kit headgaskets and when I ran the SCR and DCR, it came in about 8.2 SCR and something like 5.6 DCR so really couldn't pull me off my Throne! Sucker sounded good tho.

Notice the 2.02"/1.60" valved double-hump heads and low lift cam to keep the valves at a lower lift to keep from kissing the cylinder wall tops.

The bad deal is that the bigger valved double-hump heads are usually 64 to 66 cc's chamber size so you HAVE to install domed pistons to get the compression up there like GM did back then. They used 1/8" tall, 1/2 round domed cast pistons that can be reversed. I had a cheap $34.95 set from good ol' W/JCW in my old junk301.

You can get away w/ angle milling the double-hump heads BUT this is a real hassle that I care not to get into! Plus, it costs some money to have done!!

The 290hp/283 is 10.5 to 1 CR'd and the 315hp/283FI engine is 11 to 1 CR'd.

A small chambered set of heads so that she is right at 10 to 1, a small 224 to 230 or so duration at .050" lift solid lifter cam, a 600 cfm Holley on a 300-36 and a cheap set of 1.625" dia, 4-tube, long headers and the little-bitty short-stroked jewel will run like a "Scalded-Dog"!!

Add more of everything except headers and gear and tire her right in a small light bodied car like a Vega and go big engine hunting!

pdq67

PS., and install shim headgaskets!!

Best Car Insurance | Auto Protection Today | FREE Trade-In Quote
 
#16 ·
Thanks for your help, everybody- I just settled things by buying a set of 416's. 1.94, 1.50 58cc's. With the bolt holes, finally. Perfect for a 283, and at $339 I couldn't afford not to pull the trigger instead of machining the old schools. I 'AM' old school, though, by rebuilding the 283. Gonna spin that thing.... Rich
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top