Bad 306

[9sec93lx]

Originally Posted by goodyear1984

well u said u dont want to build a 347,just so u know keep this in mind if your buying all new parts the cost really is not much more to build a 347 rather then a 306.but if ur stuck on a 306 here are a few pointers
as far as the crank pistons rods go i would use a 28oz balance crank like a scat 9000 or better,rods i would use I beam rods rather then H beam because there lighter and u want lighter parts to free up horsepower.pistons i would use JE,srp,wisco,keith black and i would have 10.5 to 1 compression. keep in mind anything over 11 to 1 compression with aluminum head will require race gas or e85.i would deff use a main stud girdle to make the bottom end stronger.7qt oil pan with a windage tray will free up a few horsepower.i would use a bigger head then a 165,i would use a 185 head with a single plane intake and solid roller cam that will run 7000 rpm.

Everything Goodyear said above, and my 2 cents worth here. Think a lot of compression, camshaft and rpm to pull 425 flywheel hp out of a N/A 306. Using the basic hp to torque formula the engine would need to produce 372 lbs.ft. Tq if the horsepower peak was 6,000 rpm and only 318 at 7,000. Its not easy to get 372 lbs Tq.@ 6,000 rpm out of a 306 without a power adder.

Use all high quality forged internals and a good balance job and you should be okay. A solid roller cam allows you to run a much more aggressive profile than you ever could with a hydro.Use an 1 3/4 primary, long tube header or a 1 5/8 to 1 3/4 step header. MSD ignition to light it all off with.