Ever put power pack heads on a 350?

I did do a search on this first.

My 283 has some internal problem that will require that it is pulled. I'm planning on replacing it, but want to keep and old look, and have some recently redone power pack heads, which I was going to put on my 283 before it ****ped out.

OK, my question is, has anyone ever put power pack heads on a 350 to make it look old. Can you even do this? Will the compression ration be way to high for pump gas?

Here is the deal I can get a short block 305 or 350 for the same price. I know the power pack heads will work on the 305, but am thinking if they will work on a 350, for the same money, why not get the 350.

Any advise?

 

i think it'd just be really restrictive. compression would be higher for sure, but in my understanding and in research on the net about powerpak heads, the breathing just isn't there. powerpaks are really only effective on the smaller cube engines.

 

Yea. I know you are right about that. I personally would be happy to go with another 283 or 305, but some day, not soon, I'm gonna sell this truck, and a 350 wold probably help me do that.

 

I've got a 355 inch small block with flat top pistons and 64cc heads. They are World Products heads, but the chamber size is the same as your heads. It runs fine on 87 octane gas. Your ports are small but will not be noticeable except at higher rpm's. In fact, it might have more torque at low rpm's than a normal 350. Use .038" or thicker head gaskets.

 

Thanks bobw. The compression issue is what I am worried about. I just want to be able to run this baby on pump gas. I like the idea of added torque.

Basically, my thinking is that if I put a 350 in her with the power pack heads I can always put on better heads to improve performance, I could maybe do that with a 283 or 305 as well but will always be limited in potential, where as with a 350 I have more room for improvement for the same money.

 

Keep this one going.

 

since you already have them use em, will make good low end torque,like said above,put a small cam in and have fun

 

Sounds good but what is the real diifferance performance wise between HO 305 heads and 283 powerpack heads??

 

I've heard the 305 heads do flow much better, but I'm more interested in the way the motor looks at the moment than performance. So, as long as I can run pump gas and don't have any piston to valve clearance problems I'd like to run the power pack heads I have...I do have to say however, I sure like the way my 283 winds up to 7000...don't think I'll be doing that witha a 350 as much.

 

MY HP book lists compression with pp heads 64cc: 283 FT piston-8.6
305 9.2
327 9.7
350 10.3
350 dished 8.6
I am running a 327 with flat top pistons, Performer cam, cast iron Q jet intake with a 600cfm Holly, HEI in a 52 Chevy SD with a 350 trans and a 3.08 rear. It certainly will not snap your neck and uses 91 octane. Not the best combo, but it runs good and is paid for.

 

so powerpack heads on a 327 just bumps up the compression a little and keeps the valves smaller than a set of camel humps would. SO!!! you could get the early look and even better gas mileage????? but if you keep the motor stock at 9:1 comp you should be able to use low grade...........

 

what is the casting number on these powerpack heads? some 283 PP heads had 60cc combustion chambers....that with flat top pistons on a 350 chevy would give you about 10.8 to 1 compression

 

I'll check the numbers tonight after work and post em.

 

Check the cylinder head cc's. (see warning below)

Check the 350 piston to deck clearance and add if there's any valve reliefs.

Go to an auto math web site and download the formula to calculate true compression ratio. Enter all the data and you'll eliminate the guess work.

You can use different thickness head gaskets to help get to the compression ratio you want. Fel-Pro and other suppliers have a bunch listed. Normally a .038 compressed thickness gasket is the usual standard for calculating, but feed into the formula other thicknesses and you'll be surprised at the answers. You can get there from here .

Warning!! Sometimes what ya' read off those web sites tellin' ya' cc's for a casting # isn't accurate. I have some 305 heads that are supposed to be 58?cc's. Were actually about 63-64. These were OE never messed with heads. Makes a significant difference when you're trying to acheive a certain compression ratio.

Also, the small ports of the 305 and old Power Pack heads will increase the velocity of the intake charge into the cylinders which will increase bottom end torque. Add as much compression as ya' can stand without too much cam and you'll have a good streetable package.

 

I built a 350 with power pak heads back in the 70's.

I was going for a nice driver with good fuel economy. It worked real well but but ran out of breath long before 7000. I don't remember where it stopped, but while it was great for driving around it was not a race car. It was real snappy at low RPM.

I'd do it again.

 

Ok, so now I'm wondering how a 71 350 out of a Monte Carlo with my 305 HO heads would run and what the compression ratio would be, seems like it would run great with the 274 Crane cam ****** super comps Edelbrock dual plane and Edelbrock 600 carb with a M-22 and final gear of 488 in a 55 chev.or am I just being a little or maybe alot stupid???

 

OK, here are the casting numbers:

3795896 / GM 10 / 0284

3795896 / GM 8 / 0214

 

Should I use a thick gasket, and/or dished pistons?

 

Go ahead and run the power packs with stock gaskets. I say never use "thick" head gaskets. It reduces your quench area, which leads to incomplete combustion, which leads to carbon buildup, which can cause pre-ignition, detonation, loss of power. If it pings, that's your excuse to put in a cam with more duration.

 

The cam I've got has 218 duration on the intake and exhaust and 268 advertised duration on intake and exhaust...according to summitt.

 

Thanks! MorTech says my heads have 60cc chambers.

 

I've never seen an untouched head that didn't have more ccs than was listed from the factory and I've never seen an untouched block that was close to the blueprint deck height. Only way to know for sure is to measure and figure.

 

Yep, it worked about the way i thought it would. I figured it would run outa' steam at about 5,500 rpm. But getting there is fun .

I like the idea of good fuel economy for a daily driver while still being able to give the 5.0 Mustangs a good run at traffic lights .

 

Think you'll have too much gear. You won't even have to use 1st gear with that combo. Other than that it sounds good. Make sure ya' have a high volume fuel pump. Those little float bowls in that Ebelbrock carb will empty fast when accelerating.

I'm runnig a wide ratio Muncie and a 3.56 gear in a Ford 9" in my '40 pickup. Acceleration from a stop is pretty damn good. Drops 1,000 rpm during each gear change.

Had a close ratio box in it and couldn't pull off in 1st gear. That same box with 4.11's would've pulled off better but I couldn't run the interstate.

 

LS what did those internal problems that we were listening to the other day turn out to be? Is the engine completely trashed? I'm not so sure that having a 350 in the truck would affect the sale price all that much if it had a good running original size engine. It's to the point nowadays where a 283 is not really considered a belly-****on SBC. A 350 definitely is. Even a complete rebuild on the 283 seems like less h***le than scaring up another engine which may or may not work with the cool powerpack heads.

 

That's a good point to remember. Keep in mind that the 327s that Chevrolet rated at 10.5:1 compression were really 9.7:1.

 

Yeah it's alot of gear but it's alot of fun too. Right now I'm beatin a HO305 with that combo and waiting for it to die so I can do the 350.I'll probably look for a 3:42 or a 3:55 firebird rear to drop the rpm's.It turns 3200 at 50mph and about 3800 at 60.The cam is lopey enough to make it hard to get through traffic or a parking lot in 1st but when you hit it, it really jumps

 

Should be a definite improvement in low and mid range throttle response due to the increase in compression and the small valves and ports....worth doing for an urban driver for sure,but it wil not have much top end at all.....Id do it if "racing" were not an issue.

 

Choprods, thanks for your 2 cents. I'm only planning on using this thing on the street, it won't be a drag racer, although I would like it to move away from a stop light in a hurry if needed.

So, what would be alround better, given my needs? A 350 with the power pack heads, or a 305 with the same heads. I gotta think the 350 but am willing to listen to anyone who says different if they tell me why.

 

Although it wil surely seem insane to most -I suggest a 305.
IF-It just makes sense that the mission/end result be driveability ,and not speed the 305 wil be less apt to suffer the top end malady we all suspect.
IE-the lesser Cu In will require less fuel air flow and so flat top end will be less noticeable...
I also believe since it shares the rod length and stroke of a 350 /even though less cu in-it would be like a damned tourquey 283 with more balls!
I would keep the camshaft sensible so as not to undo the aforementioned gains....for head gaskets I will suggest the blue Felpro gasket for the 350.

for cam:Id suggest a 350 horsepower 327 Hydraulic cam of about 450" lift....even tho it will be noticebly less lopey [in the longer stroke 305] it will aid midrange breathing without requireing a stall convertor or a rear end ratio that is too low for hiway use....sounds like a good plan to me-although this is all speculation by a purely "seat of the pants engineer's " dyno....