Sbc 400 vs 415 vs 427?

[mtrhead]

Why not use the 5.850 rods? Available and provide more cam clearance. Use a 1.25 c/h piston and let piston come out of hole .012” or use custom pistons, or just use a slightly shorter stroke crank if you don’t like a slightly positive deck.
When buying a new crank custom work that doesn’t cost much more. If you called a place like Callies they’d hook you up with right crank for not much more than standard.

[steve cowan]

this is how i figured what should have happened :

383 - 423 = 40 cubes = 40 hp gain minimum
2 points CR = 25 hp ? gain
850 - 1050 carb = 10 hp gain ?
also put on a real high dollar oil pan at the same time. = ?? 25 hp over a stock pan at high rpm ?

100 hp guesstimating. Would like to try a different cam, maybe the convertor you mentioned ?

If it’s going through the lights above the hp peak I’d think maybe you’re out of gear. I’m no expert, but if the converter is too loose or you’ve got too much gear at some point those things that helped a smaller power plant start to become a limiting factor with bigger torque and power numbers. Like telling Lance Armstrong in his prime to race the flat straights in his lowest gear.

In a drag racing application
Ideally you want to rpm 1000 rpm or so above peak hp across the finish line, this is why you over rev the engine on the gearshift, having stall speed 500 rpm below peak hp is favoured as well but not always appropriate depending on vehicle application, in order for this to work effectively you need the engines induction system and camshaft valve events to suit application, in a street /strip deal there will be compromises and hp peak rpm will need to be lower,having a street engine peaking at 7000rpm might not be the best situation, I have used stall converter at 5600 rpm in a engine that peaks at 6000 and always ran a couple tenths faster than with a smaller converter stall Eg,4000 rpm stall
When you see guys whose engines and vehicles punch above there weight running fast it tells me they're combination is complimented with correct engine parts for application, very rare especially in a street car deal, most are over headed, over cammed, under convertered or rear gear, startline gear ratio etc, but it is a stack of compromise.