General Category > Quadrajet Carb Talk and Tips

Stump puller or Old Faithful?

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Stripes:
Hi Cliff,
My 469 with the 7k3 heads and the very mild cam finally broke a valve spring and its time to replace the heads and move to a hydraulic roller.

I plan to use a set of d-port Edelbrock 87cc non ported heads on the 469, iron intake, long branch exhaust. Stock crank and cast pistons.  My 69 Firebird convertable weighs about 3300 lbs, has a 700r4, 3:55 rear gears, a 2200rpm convertor, and a quadrajet.

I know you like more duration in a big 469, and a wider centerlines. So, I'm torn between a 230/236 @50 hyd roller on a 112CL, or a 236/245@50 on a 114CL for a street fun type vehicle, not a race car. So really the stump puller or the old faithfull? I've got power brakes, AC, and power steering.

I feel like the 230/236 would be enough duration, but with my past issues, I'm unsure.

Cliff Ruggles:
What is the compression ratio going to be?

Stripes:
455 .60 over(4.211), stock 4.21 stroke, flat tops, 87cc aluminum chambers, .045 compressed head gasket, estimated compression 10.12-1 with 0 deck clearance and 8cc flat tops calculated.

I didn't build the engine and don't have the old heads off yet, so I don't know deck clearance, but I will check it before I order the heads. I suspect 10-1 compression is a good estimate. (using Butlers compression estimator) If the pistons are down .020", then 9.74 to 1 is likely the lowest it could be.

I'm also considering a performer RPM intake. But that is easy enough to swap back and forth between the factory manifold. I know you indicated the factory intake was the best, but I'm unsure if the performer rpm was out at the time?

Cliff Ruggles:
I dyno'd my iron intake, an HO (re-pop), and an RPM back to back on a 500hp engine.

All were port matched to a stock intake gasket.  The HO made 487hp, the RPM 491hp and the iron intake made 497hp.

Yes, it made MORE power than the taller and difficult to fit under the hood RPM intake.

So to at least 500hp no need for the RPM intake. 

I'll also add here that when you shove the carb up closer to the hood and start adding parts like drop base air cleaners/shorter air filters and such for clearance, they can rob even more power.

Plus it takes a little "cobbling" to use the RPM, throttle cable bracket needs shimmed up, hard fuel lines woln't reach the carb inlet, etc........Cliff

Stripes:
OK, the iron manifold lives on.

Regarding hydraulic roller camshafts for this 468 edelbrock D port headed (251@.500 I) engine with long branch manifolds, I feel like I have narrowed it down to 3 cam choices. I realize all will function, its just a struggle knowing how much is too much or too little.

1. 230/236 @.050 on a 112 with .510/.521 lift
2. 230/236 @.050 on a 114 with .510/.521 lift
3. 236/242 @.050 on a 114 with .520/.540 lift

Which or what would you recommend?

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