SBC two bolt main block, reasonable race power limits
 

To have a reasonable answer for my question, allow me to explain this SBC will be properly assembled and tuned. Also, it will not be abused by overheating nor run with denotation.

The application is a, dedicated, trailered, IHRA Crate Motor car making about 450 - 475 horse with an upper RPM limit of about 7100 RPM. [auto trans]

Are any SBC engines racing at that power level with two bolt mains and giving satisfactory service life?
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Re: SBC two bolt main block, reasonable race power limits
 

I have a 2 bolt block making over 500 in crate motor, steel heads.

Re: SBC two bolt main block, reasonable race power limits
 

Larry, i have some LT1 engines that turn around 7800, with no problems! The Horsepower is more than what you are speaking of!

Re: SBC two bolt main block, reasonable race power limits
 

My personal opinion here but here it is:

You cant give a HP figure on it, You have to know the weight of the rods and pistons and RPM

With lighter parts i feel you can push a little more HP and RPM

The reason you go to 4 bolt is your trying to push the caps off the engine and this causes "cap walk" if the load is not enough or the cap material is not strong enough, solution? Stronger Milodon caps or 4 bolt mains for increased clamp load to prevent cap walk and/or stronger material when using Milodon caps

With heavy parts and 7,000rpm i think it will be an issue, what i mean by heavy is 700gram rods and 600+ gram pistons

The lighter parts are gonna put less force on trying to push the main caps out of the engine as you turn the RPM up

Do you have an idea on the piston weight, rod weight and HP the engine may make

I feel a factory two bolt with a conversion to Milodon caps are best where the outer bolts are splayed which makes it harder for the cap to walk because the way the spalyed bolts preload the cap - But if a class rule stops this then you must go by the class rule

Can you give some insight on the weight of the parts your slinging around in the engine?