[dwmiles]

when building a small block, I understand that by using 6" rods with the proper pistons, you can run a higher c.r. using the same basic fuel (92 octane) and thereby produce significantly greater h.p..due to the bore to stroke ratio increase..can you do the same thing with a 468 and run, for example, 11:1 pistons for a streetable 70 SS LS-5?? what would be the best combo using the L78 cam and the Vette tri-power intake with LS-6 heads?? thanks in advance..BB Dan

 

[Ryan Hoskins]

Dwmiles,

I'm a little unclear on your post: you mentioned the use of 6" rods in a small block, and then mentioned bore/stroke ratio. If you are talking about running longer rods and increasing your rod/stroke ratio, YES, there are benefits. Less rod angularity, less side-loading, more piston dwell, etc.

With big blocks with a 4" stroke (454), you can run upto about 6.535" rods, which are +.400" over the stock 6.135". If you run a tall deck block, you can run upto 6.800" rods, for a rod/stroke ratio of 1.7. Much better than the stock 1.53.

A higher rod/stroke ratio WILL allow you to run a slightly higher compression ratio with the same fuel before detonation, but I wouldn't say significantly more HP.

Something to keep in mind if you are buying rods and pistons, since they are the same price as stock in the aftermarket. I am currently building a 505 with a tall deck block, and I'm running 6.700" rods with a +.250" stroker crank. I'll let you know how it works!

If you were talking bore/stroke ratio, I misunderstood you.

Ryan

[This message has been edited by Ryan Hoskins (edited 12-21-1999).]