Performance gains on a 1979 z28.
 

Hello, lll keep this short but a little backstory. Picked up a 1979 z28 about 2 months ago. Had some welding done on it so the frame and body will pass safety and now were moving on to the engine. My main question is what kind of performance increases can i expect with my new parts

https://scontent-sea1-1.xx.fbcdn.net...17&oe=55FF7F5B

Were totally rebuilding the top half.

350 v8 sbc stock with 3.43 stock gearing, 3 speed TB350 trans.

What we have:

-Stock 650 cfm 4brl carb

-Ken Murray rebuilt CAST vortec heads. Totally rebuilt and slightly modified. (64cc)
I wish we had more details on this because I'm not totally sure what has been modified as it's generally beyond my knowledge, they are back to like new condition, and were re built with racing in mind, but are still cast, Ken Murray is a famous drag racer and mechanic in my area and friends with my father, thats the only reason I was able to get my hands on these heads.

-Crower Torque Beast Performance Level 3 Camshaft 00904
http://www.crower.com/chevy-262-400-...aulic-cam.html

What we dont have but will shortly:

-Aluminum intake manifold. Not sure which yet, possibly rpm. (any recommendations?)

-Headers (hopefully long) Just gonna get the best deal, if theyre covered in surface rust well paint em, were not building the car for world of wheels.

-Re using stock exhaust pipes for now.

-Possibly replacing the stock fan with an electric. any reccomendations?

Anybody have an idea? In a perfect world i would LOVE to have 300hp at the rear wheels. But because of the low starting point (175) im not sure if itll happen without doing the lower half as well. Its already a light car with half decent QM and 0-60 times for how gutless the motor is so any increase will go a long way.
Were not trying to make it an 11 second car, more of a fun car with some power and a classic look and a decent amount of power.

Thanks! I apologies for any bad formatting or grammar, this was written on my iphone.

Im 21 and this is my first muscle car project.

Without addressing the low compression 8.2 to 1 you are not going to see huge gains. Your heads could have less CC which will help but I think you are stuck with dished pistons.

It has been a long time but I think the 79 came with a cast cranked, rods and cast pistons. If you could get it to 300 hp you better be careful. Normally a 8.2 engine would be perfect for a turbo but I know those piston would not last.

64 cc heads. Stock was 75cc. Compression should be elevated when said and done.


Oil pressure and compression tests were solid, engine, and tranny match the car and powertrain, drivetrain and body are all at a matchin 127000k

I don't see a problem with the cast crank, rods, and pistons, or two bolt mains, even over 300 hp,. I do agree that the smaller chambers will bump compression a bit, but not sure if it will be enough to hit 300hp, even with the changes. Should easily be over 8.5:1 c.r., and maybe 8.75:1 even.
You could probably toss all the specs into an online calculator, and see what it spits out for a guesstimate. Regardless, it will be a big improvement over the stock HP rating.

https://scontent-sea1-1.xx.fbcdn.net...17&oe=55FF7F5B

Heres a picture of when we got it for anyone interested, and don't worry, well but levelling out the back.

So from what I can tell most people predict I'll be hitting roughly 250hp, but we won't know for sure unless I test it, I also know that these heads have been designed for racing by one of the top racing names in my province and country (google ken murray manitoba)

It was a $2000 job and they ran into issues with who they were rebuilding the heads for, so he never totally payed him and which is why I was able to snag them.

I'm not sure whats been modified, as knowing the head CC is as far as my knowledge goes, but I know he hand picked out camshaft as well to go hand in hand well together and give me lots of power.

without touching the crank or pistons, does anyone have any ideas for getting another 50hp? I suppose 4.11 gearing.

I think you are under rating those vortec heads for what they will do for you. It should raise the compression one full point to around 9.5-1 if you use a .015 steel shim head gasket with the pistons .025 down in the hole and the shim you should be close to a very good quench at .040. The only thing I might change at a later date would be to get a set of 1.6 self aliening rockers to give the cam a little more lift. HP might not be the greatest but the TQ numbers are what you will feel in when you get on it. For the intake a air gap if you have the room under the hood or just a performer will get it done. I would keep the stock fan with the declutching fan as is. It only comes on when the temp get to high. I have done a lot of these vortec motors with cams close to yours and all have run deep in the 13s if everything is set up right. Let us know how it goes when you have it done.

Thanks, and absolutely, I'll post my results when it's done, should be mid june when I finally get it driving.

High 13's is realistically what I am hoping for.

For all we know as well the lifters have been changed, i'm not 100% certain but I actually believe that they were changed, if not upgraded, at least replaced.

Is there any way I can determine this just from looking at them?

Doesn't really matter if the lifters were changed or not. Considering all you have planned for the engine, do you really want to throw used lifters on a brand new cam? The cam will break in to whatever imperfections the lifters might have. Good lifters aren't that expensive, and I'd never use anything but new on a new cam.

Will look into this, thanks-

again, any recommendations?

Lifter recommendations, or how to check old lifters? Since I refuse to use old lifters, I wouldn't bother going into how to check them. As for new lifters, I prefer either Comp Cams, or Howards, as their lifters are both US made.