BBC OEM crank, rods HP capcity/build... sugestions please

[malibu795]

Re: BBC OEM crank, rods HP capcity/build... sugestions pleas

Bringing an old thread back to life..

Got roughly 50,000 miles on this engine combo.. Who knows how many miles on the OEM crank.. Got a rear main leak.. Pretty sure it has a Grove worn in it..
Had build thread but it's disappeared..
Has 781 with 2.065/1.88 valves, edelBrock performer intake, same mentioned camshaft, 600 cfm edelBrock carb msd ignition 68610? Headed dual 3" exhaust
Dyno'd 305/430 at the tires while back.

Got a virgin BBC in storage with eagle esp cast steel 4" crank 6.135 rods.. Haven't bought pistons yet..
Thinking buying a 4.250 crank making a 496 and take the 4" crank replacing the OEM crank on my 468.
Convert to HR with 112°ls and duration @.050 220/230° with 9-9.5:1 cr
Get fast ez-efi on the top
Should be fun with the 3.08 gears

 

[grizwald]

Re: BBC OEM crank, rods HP capcity/build... sugestions pleas

I'd say more carb/cfm is in order! 600 cfm would be right at home on a 305! Pretty decent numbers considering the small carb though!

 

[malibu795]

Re: BBC OEM crank, rods HP capcity/build... sugestions pleas

I'd say more carb/cfm is in order! 600 cfm would be right at home on a 305! Pretty decent numbers considering the small carb though!

If I had shorter legs ID have a 750 on it.. 3.08 gears it boggs/floods out.. Hauled a Dmax long block from Ohio out to Denver Colorado. Running 75-80mph avg 16.5 mpg. Usually see 18mpg @65

The 468 with 600cfm will pulls to 4800-5000 then exhaust goes black. Vac secondary open about 2300. Rarely open secondaries due to I catch traffic pretty quick.
The ez efi would be nice 1000cfm intake

 

[1981Regal]

Re: BBC OEM crank, rods HP capcity/build... sugestions pleas

I have a 750 on mine simular setup but more compression and small thumpr flat tappet cam. No where near that mileage though. Need some carb work.

 

[malibu795]

Re: BBC OEM crank, rods HP capcity/build... sugestions pleas

Mpg is more then just carb tuning.. Definitely plays a part.. Definitely going to be hard to get MPG out of the th350, but not impossible.. Definitely would have to play towards the BBC tq

 

[1981Regal]

Re: BBC OEM crank, rods HP capcity/build... sugestions pleas

Ohh.. Totally forgot you have a T56 sure that helps a lot. I've got 2.41 gear as well so it doesn't buzz too hard on the highway.

 

[malibu795]

Re: BBC OEM crank, rods HP capcity/build... sugestions pleas

What TC do you you have stall wise?

 

[1981Regal]

Re: BBC OEM crank, rods HP capcity/build... sugestions pleas

Stock.. need to get a good stall. I think this th350 came from a 78-79 Camaro.

 

[malibu795]

Re: BBC OEM crank, rods HP capcity/build... sugestions pleas

What's all done to the BBC?
One thing I found with long gears 750 carb it too big too DD. A 600 and a ~2000 stall would do wonders for DD. You'd lose top end but gain off idle and part throttle response

 

[1981Regal]

Re: BBC OEM crank, rods HP capcity/build... sugestions pleas

I bought it built knowing what I know now I would change a few things.
60 over - 340 dome pistons - 781 heads stock valve size - rpm intake - 1407 750 edelbrock
Has to run 93 or better. I heard it running freshly rebuilt shaking the ground and rattling my ears and lungs. It was pretty much over at that point in time for me the engine came home with mr