Hey guys.. Need an opinon.. I have an 81 vette that I am getting back up to speed. I was thinking of some other ways to make it perform a little better... First off, it has 190hp engine w 8.2 cp and a small cam and 2.87 rear gears.. Now I am not new to this, I have worked in the auto field (Import car dealer for 16 years (HONDA)) I am an A-tech, but at the dealer, I fix the cars, I don't hot rod them. I have done a ton of Checy engines and mods years back, but I need some input..
We know the car is a slug, so I had some ideas here...
I have a Holley 750 single pump dual feed carb I just rebuilt. Thinking of disconnecting the computer and installing this carb (The Q-jet needs major work, should send it to a carb shop and have it done correctly, I am good with the hollleys, but not electric Q-jets. Anyway, Was gonna put a comp cam 262 or the voodoo cam witch is about the same as the comp cam but it it 256/262 duration and a little higher lift. I have a regular HEI with vacume advance also. Do you guys think I would have more torqe with the Holley and cam and HEI vs computer set up??
I might also put a set of 3.73 gears in the back to get that seat of your pants pull out, but I am not sure if any of you guys have done this.
I am not tring to go like a bat out of hell, but wanted something that at least will keep up with a honda civic, if you know what I mean.
I also don't want to spend a ton of cash on an 81 vette. It is a really nice looking car, but what a slug.
Oh, I was also considering headers. I put on flowmaster mufflers and I put a test pipe in place of the cat. I really don't care about emmisions because I am an emmisions inspector...It will pass, trust me.
An opinions would be helpful..

 

 

What is "not spend a lot of cash"? Give us a budget here.

BigBlockk

Later.....

 

The Q-jet is a better all around carb then the Holley, and in the application your talking is a better choice. The question here is how much cam will the old computer tolerate and still give you good gas mileage and performance. If your going to go that far into the engine an older non-computer controlled q-jet would be more tuneable to your application and still keep most of the gas mileage. You'll deffinitly need to change the gears to get any sort of decent acceleration out of it, the best compromise gear is normally a 3.55, with 3.73's you start to cut into your highway usage but acceleration would be far improved over a 2.87


Pat Kunz

 

OK, my recomendations for an 81;
Keep the e4me, use the computer and stock dist.
change coil and ignition module to one of the HOT Rod versions, accel or Malory
Bump up the cam a bit, add on headers and true duals put the O2 sensor back in, lose the smog pump depending on local emissions, and if budget permits better heads for better comp ratio...9.5:1 os thereabouts.
start with that and see how ya like it, the ECM should take care of the primary metering jets with no changes, the secondaries might need some tweeking.
Want a lil more? Change to 3.7:1 in the rear and a 3004r trans, that will give you the quick hole shot plus longer legs on the hiway. you can reasonably expect to get all that for well under $5k, a lot less if you got some skills. All the help you need is in here to make it happen.
Before doin all the HP mods however, that car is 25 yrs old, make sure brakes and suspension are up to it, new bushings, ball joints, rotors and calipers. Lots of choices on rebuilds.

Good Luck, post some pics

 

1. A stock 190 hp '81 does the quarter mile in 16 seconds, faster that a stock Civic I believe. There is more to speed than hp specs, please refrain from calling my baby a slug!
2. I have put the comp 262 cam, Shorty ceramic headers, true duals, MSD ignition and Edelbrock manifold and can spin the rear tires with the computer, distributor, q-jet and rear gears that came on the car.
3. Please post where you do emissions inspections so your buddies here on the forum can "pass, trust me..." also!

God bless, sensei

 

See what many refer to as my Exhaust topic.
http://www.corvettefaq.com/c3/ganeyexhaust.htm

Sounds like an auto. trans w/ those rear gears hence your concern for torque. 600 would be better or Q-J for torque. W/ 3.7 gears the 750 Holley would be fine.

 

I am not really sure of the budget.
Here is where I am at so far..
holley 750 given to me plus rebuild kit ($25.00)
Comp cam and lifters $200
Set of gears from buddie 3.73 ($100)
HEI from buddies junk yard $10
Test tube (free)
GAsket set $80
Set of 64c chamber heads done of 1970 pass car Done $300
Intake performer $115
odds and ends $100

From what I read in the opinions I could have my Q jet pro rebuilt and continue to use the stock dist and intake. Remove the smog pump and install a 262 comp cam. Best bet sounds is to get a true dual exhaust also. Think the Holley is not such a good carb for what I want.
I am not sure if I should go as far as putting these better heads on , but I might. Think the cam will like the higher compression ratio. I didn't cc the set up, but I bet from going from 8.2 with 76cc heads to 64 cc heads I should be about 9.2. Not sure, but that has got to make a difference you would think.

 

If it's about 8.2:1 w/ 76cc now ... 64cc will make about 9.2:1 ... IF, IF it has a thick composition gasket now w/ 8.2:1 ... a thin steel shim gasket (0.015") FelPro P/N 1094 will bump CR about an additional 0.4-0.5 ... to a potential 9.6:1 - 9.7:1 CR w/64cc. Heed Ganey's exhaust research, a good Qjet & good early-style 4-pin HEI w/vac & NO ECM will do wonders. I'm not a big fan of comp cams ... but their 268 might do a better job for a ~9.6:1 combo than 262.

 

while my 72 is different, similar scenerio. started with 200hp and went to 10.5 compression, and a mild cam....but the carb is where all the problems came from. Started out with a Edelbrock, the shop (and all they do is old vettes) could not dial it it...then went to a holley, ran like crap till it was really warmed up and even then had a serious hesitation when you hit the gas, then they called me and asked me to bring my Qjet back to them. Rebuilt it up to a 650 and this is the first time the car runs GREAT !! starts better, has great cold idle and runs great when warm. I don't know if I lost some HP in the deal but i'm so happy to have it run great I don't care, as my goals were never to leave most of my tires on the road...just my 2c, but I did a similar post question as yours months ago, and didn't take the Qjet advice everybody gave me, and now, months later, back to my QJ !!

 

I don't know what's with people having trouble with Holley's.

I've run them for over 170,000 miles (three different engines) with no driveability problems. I don't run chokes and the engine's have always started well and were idling on their own within a minute (3 minutes if below freezing). I'd recommend a 600 single pumper for the relatively mild engine you describe. A 600 will handle up to 6000 rpm (350/350 HP type cam or equivalent).

 

What do you think of the new line of voodoo cams from lanati?? I wonder if voodoo is just a neat selling name. The profile on the 252/262 cam looked pretty good for what I am after. What do you guys think?

 

If you got the holley and the kit I would use it. Here is my take on the whole Q-jet versus Holley. I the right hands the Q-jet is the better carb. But it takes someone who really can tune one. That is hard to find. I have built many Q-jets for stock applications. Now a Holley is very simple to tune and tweak even for a Novice. There is not much there. It is a pretty forgiving carb. Both are great for power. So in the right hands a Q-jet can be a great carb the Holley is just simple and they work well.

 

 

I agree that the Holley is easier to tune. I am sure I could rebuild the Q-jet myself, but it is an electronic q-jet, and for some reason I just don't like the fact that it is electronic. Another thing I don't like is the fact that is is controlled by a VERY SLOW STUDID COMPUTER. Computers in cars these day are 10000 time faster and much more input/output than this thing. Also saying that, I am not impressed too much with the computer controled dist either. Think I am gonna do the Holey. I would consider a NON computer Q-jet, but not the one that came with the car.
Now that we have the Carb situation figured out what gears and cam do you thing I should run with? I don't know if I am shooting for the moon, but I would like to be close to 14sec 1/4 mile car.

 

With what you're building, forget the Holley. If you're in the vac-secondary market, the Q-Jet is the best play,..it flows 750 cfm,..the timing of the secondary air valve opening is very easy (e-mail me if you need directions),..the gas mileage WILL be better,..and the tuning for WOT is a breeze without removing the carb (secondary rods changes take less than one minute,..changing jets on a Holley means taking apart the carb).

I've not found vac-sec Holley's (i.e., the 850 that comes on 502 crates,..the standard 3310,..the original 4346 (780 cfm for 396's in 69), etc, NEARLY as easily dialed in as a Q-jet. Holley's PV's (2.5 to 10.5), vac-sec springs (Yellow to black), accel pump cams (white to brown) and accel pump adjustment, etc, all need to be perfect for your engine or it will disappoint. Not so with the q-jet.

But forget the smogger q-jet,..find a useable/rebuildable version that is stamped 7044xxx or less numerically (1974 and earlier). The smoggers will run much too lean for performance apps.

On the other hand, I've found Holley double pumpers a breeze to tune,..they're more stupid like me.

My opinion,
Wes