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It's back! The sweet sound of 7000


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...but not with my carburetor. Rob was generous enough to pull his boat carb off and let me give it a try. Instant revs to 7000! Now I just need to find why mine won't flow. I've blown out everything. At least the problem is located. Anyone know if metering blocks, front/rear can swap locations?

JS

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Guest Anonymous

John,

 

What type of components are you using in your bottom end (crank, rods, pistons)? Also, is your engine internally balanced or externally balanced? What type of dampner are you running? And, are you running a 302, 327, 350, etc...?

 

The reason I ask these questions is because I am doing some research now on my engine build, although it is still some ways off in the future. Back when I raced go karts I ran "Sportsman" class which was basically a stock motor with a race induction and exhaust. We used to have problems pulling the wrist pins out of the bottom of the cast pistons rather frequently, if you can imagine that was quite noisy!! My Dad ran "Open Modified" and always ran forged pistons and billet rods, they would rev those "Open" motors to the sky and never had any failures.

 

The folks at Scat advised that their 9000 series crank (internally balanced w/ preferably no dampner), cap screw I beam rods and Wiseco forged pistons should be safe to 8000 RPMs.

 

I doubt I would EVER rev my motor over 6500 but I like the idea of "built in" insurance.

 

Thanks,

Chris

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Chris, the 4.3 in its stock form was used in the Gran Mark series. 7000 was considered a safe rpm for the stock rods and crank. In a previous engine swap, Toyota Hilux, you wouldn't believe the abuse I gave the engine w/o failure for 150K miles. I've prepared my crank and rods, by the Chev. power manual. Indexed, crossdrilled, rods polished, shotpeened, high end arp bolts, and run a Fluidamper, all balanced by the best in the area. I also run 7.5:1 forged pistons. My Machining bill would make any V8 proud frown.gif . I agree with you on the V8s. On most stock Chev.s I wouldn't take them past 5600!

Back to my carb. I disconnected the secondary side and it revs great. Everything has been blown out for the 3rd time inside and out. I have a clean shot from the jets to the boosters. All air bleeds are clear. All gaskets new. The thing is and always was really clean. Something is ruining the secondary fuel distribution. Now I want to try a different metering block. I was wondering if any will fit as long as it came from a double pumpr? Mine has the non-pv metering block. Not the plate, but the block w/o machined area for pv and idle circuit.

JS

 

[This message has been edited by John Scott (edited November 05, 2000).]

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