Like I said, I need help.

I have a '77 L-82 4 - speed, with the stock block, pistons, connecting rods, and crank. I have Edelbrock Peformer RPM heads, 64 cc, intake valve 2.02, exhaust valve 1.60, and a max valve lift capability of .575". I am running the stock rocker arms with .100 long pushrods. Performer EPS Intake manifold. Comp Cam, gross valve lift is, intake .477, exhaust .480, duration at .050 is, intake 224, exhaust 230. Exhaust is headman headers, 1 5/8" full length, out to 2 1/2" pipes straight through, with H pipe, to magnaflow mufflers.

I currently have a 600 CFM edelbrock carb and I had it dyno tuned to 272 whp, and 314 wtq.

I am currently considering qoing with a larger carb, maybe a 650 or 750 cfm for more power. I would like to stay with edelbrock as I have had one holly 600, and 2 demon 650's, all of which did not function properly. 1 had a fuel leak, 1 would not stop flooding the engine, and 1 the secondaries were jammed. All were brand new, and all got returned. The Edelbrock that I have now fired right up and took about 30 minutes to tune to put down the above stated numbers.

I am also thinking about changing the rocker arms to 1.6, or 1.7 ratio.

I really want to get into the 310 whp plus range without messing with the bottom end of the motor. Does anyone have any reccomendations as to what will get me the most power while just changing the carb and rocker ratio.

I am also concerned that if I go with a 1.6, or 1.7 ratio rocker that I will not have sufficient clearance between pistons and valves. Does anyone know if I will have issues in this area.

One more question is that I also need a new clutch as the stock one is now slipping due to the few extra ponies. I have been told that the centerforce dual friction is a good choice but I want to be sure that I am not going to have any issues if I decide to take the car to the drag strip some time. I would be running street tires as I do not want to risk damaging other drivetrain components.

Any help or advice would be greatly appreciated.

Thanks,

WRC7732

 

you may get a little more power from a 650 cfm double pumper, but i'd say the one you have is probably fine.

have you considered switching to electric fans? underdrive pulleys? not sure what sort of accessories you have, but lose your A/C and you can free up some more rotational resistance there.

you say you had it "dyno tuned". did they adjust the jetting at all? i'd say you might have something to work with there by spending some more time testing different A/F mixtures.

good luck

the blonde weasel

 

Try checking some back threads on clutches, you'd be surprised at what you read...there have been several people who have had problems with CF dual friction clutches.
Also, what is your rpm range? L-82 have 4 bolt mains I'm told, with good solid bottom ends...care to run the car up to 6500?
You might also have some luck running a hi-rise intake, which should fit under your hood (but I'd check some previous threads to make sure).
Good luck, I'm trying to do roughly the same with my engine (I'm running the same cam as you comp cam XE268)

 

I'd get the clutch fixed first. If it's slipping you're probably not getting all the power to the real wheels to get an accurate measurement.

600 carb seems kind of small when you consider the factory Q-jets were rated at 750-795 CFM.

Is there enough pushrod-to-head clearance to keep the pushrod from rubbing against the pushrod hole in the head with higher ratio rockers? I'd like to bolt on a set of 1-1.6 also.

 

After the clutch, you definitely need to address the rocker arms. I can't seem to find it right now but a while back a survey was done on rocker arms, stamped, roller tip and full rollers. The stamped rockers varied by as much as 12-15%. Not to mention the extra stress on the valve train. As far as clearance that shouldn't be a problem at all, I have a flat top motor w/64cc heads and valve lift of .575".