88BlackZ-51

Anyhelp would be much appreciated! Car is an auto with the stock gears(3.55).

AGVI

I think stock gears in an '80 are 3.07 :D

88BlackZ-51

i saw 3.55's on a website.....3.07's are better for the highway.

any ideas for 300 HP?

Old Black Chevy

AGVI is correct. The '80 model stock gear was a 3.07. An upgrade is a 3.54. I'm doing that now to my '80. The 3.55 was for '79 and older.

Enjoy your rebuild. Horses and torque - it's all fun.

Old Black Chevy/Travis

AGVI

Someone give this guy some ideas! :lurk:

verskel

Cylinder Heads & cam make the most power on a stock small block.
Checkout this site for casting #'s (if buying old heads) http://www.mortec.com/castnum.htm
I'd stick with 64cc to 70cc on the chamber size and 202 valves if you can find them. Yours are probably 76cc which is typical of a 'smog' motor.

The cam should be mild and around 270 - 280 Duration .....a good Comp Cam does wonders......checkout www.summitracing.com

While you're there you can lookup the Aluminum Heads which are by far the best for performance.

I'd also look at upgrading the intake to an Aluminum Edelbrock Performer.
.....that will eventually lead to a carb. upgrade as well like a Road Demon.

Headers are 'optional' ....they'll help only after you start modding.

The important thing to know is that there are dozens of ways to accomplish this and 100's of manufacturers and part numbers out there. I'm sure you'll get a wide range of answers. Just go with what you think is best based on your responses.


[Modified by verskel, 4:08 PM 3/12/2004]


[Modified by verskel, 4:16 PM 3/12/2004]

SanDiegoPaul

See my sig for details

My block is a four-bolt main (OEM was nOT) and it got the 383 stroker kit with forged pistons and steel crank. I used a 4.94 lift Comp Cam with 1.6 roller rockers, effective lift being well over .500

Being a stroker, it handles the cam with no lumpy idle problems, using the Turbo 350 transmission. The trans has had a hardened sprag installed with a rebuild and then a 2500 stall convertor to help launches. It comes off the line GREAT!

Heads are GM cast iron issue with 1.94 valves. I used Stainless Steel valves in the heads and they were ported/polished. A Performer intake was also port matched to the heads...for whatever that's worth. My torque compared to the OEM L-48 is amazing. I'm getting a bit over 300HP at the wheels so I figure it's doing one horsepower per cubic inch.

I used an Edlebrock Quadrajet (790CFM) and the setup now has about 10K miles on it since being reborn. Next comes interior and A/C!

Down the road I want AFR aluminum heads but it can wait - I'm having boat loads of fun the way it IS!

:party:


[Modified by SanDiegoPaul, 2:29 PM 3/12/2004]

Vette'78

What sig?

SanDiegoPaul

Look at my profile

Vette'78

My bad I see it now :leaving:

redwingvette

Heads and intake will help but a cam is all you realy need to get to 300HP. Corvette Fever did an article back in 96 on how to get to 326 HP and keep everything looking stock. I can Email it to anyone that wants a copy. Send me a note if interested. They used a Crane Cam (#113942), Flat top pistons, and a lot of head work (larger valves, porting, screw in studs, roller rockers, and larger valve springs). I went with the Edelbrock heads because it would have cost more to re-work them.

American Boy

If you keep the stock gear, the cam should be near 260 advertise duration or under. Otherwise, you'll loose too much low end torque. So a nice cam would be the Comp Cam XE-262 that you could use with your stock heads. For 300 hp, you don't need aftermarket head IMO. You have already an aluminium intake so you could use it or go with the edelbrock performer. The exhaust are very restrictive so a dual with headers and good muffler would put you right over 300 hp easily. All that must be combine with a nice distributor curve that get 36 degrees at 2500 rpm and good carburator setting (jets, metering rod and adjustement for the Q-Jet).

If you want more than 300 hp, then you can go with some Air Flow Research 190 aluminium head, wilder cam, edelbrock RPM intake (hood clearence issue), differential gear 3.54 or higher and so on... It all depends on what you want and how much $$ you're ready to put in.

I got 220 hp out of the stock L-48 just by tuning it. That was without the cat and emission stuff.

Stephan


[Modified by American Boy, 9:10 AM 3/13/2004]

Ganey

Easy. Ex. is first, see if your ex. is stock single. See Why Exhaust is problem for HP on 75-81
what many refer to as my Exhaust topic. http://www.corvettefaq.com/c3/ganeyexhaust.htm

Cam, even HE260H (Min.) can put over 300.

Ryan77

It depends on how much you want to spend. You can make 300hp fairly easily as Ganey mentioned above. If you have no emmisions requirements in your area, the by all means a pair of headers, 2.5" true dual exhaust (with X or H pipe, even better), no cats, and some high flowing mufflers would be a great start. As for the motor (guessing that $$$ isn't a problem) a decent cam like Comp Cams 260H, 268H, or 262XE would be good choices. Throw in a pair of Edelbrock Performer RPM cylinder heads and a Performer or Performer RPM manifold. You can do all this with the motor in the car, or pull it out. If you're willing to pull the motor, it would be a good idea to rebuild it and be done with the motor and not have to rebuild somewhere done the road. At the power levels you'll be producing a basic engine kit will do the job. Summit Racing has kits with everything you need for the bottom end of the motor for under $900. Their kit comes with all the gaskets, a new cast crank, new rods, flat top hypereutectic pistons, oil pump, timing chain, etc. This combo with your choice of cam should easily make you 350hp and be a perfect daily driver.

Just to give you and idea of how much this would cost:

Edelbrock intake: $125
Edelbrock heads: approx. $1000
Engine kit: $879
Cam kit: $300
Machine/assembly work: $1000
Total around $3500

The crate engine route is another very good option. The GM ZZ4 is very popular, it comes almost complete, you even get a water pump and distributor, just a add a carb and things like plug wires, etc. You get an aluminum head motor with 355hp and 405ft/lbs of torque for $3700, and about $500 for the carb, wires, etc an you get a complete engine for $4200, and you can save your original motor :cool:

Hope this helps, there are tons of options out there. No matter what though you should definately do the entire exhaust system :cheers:

80TPIVette

Hey redwing, I am interested in what they have to say. Please send me what you have to randall.reed@tyndall.af.mil

Thanks!!

88BlackZ-51

thanks for your help guys.

PROSOUTH

I suggest the 330 hp GM crate engine that is a relly good buy.The ZZ4 or 5 if you have more to spend. You have a warrenty and don't have to worry about shoddy machine work or the lack of component compatibility once you are through. That's what I did for mine and came out with a ZZ5 385 fastburn crate engine. Jim

AGVI

:confused: