[Jay S]

https://butlerperformance.com/i-2553...tegory:1234783

Butler’s rate there 500557 short block assembly for up to 500 hp with a 3.75” or a 4” crank......BUT

I called Jim Butler and asked him about what they recommended. He told me 350 HP mild street build with up to a 4” crank. He seemed fairly comfortable with 400 hp, after that came the qualified reluctant answer. Maybe he is a little more conservative than his kids.

I probably should have listened to him.


We have 2 500557 builds going on. (First is like Paul K number matching example)... One in my number matching 77 t/a and the other in our 68 GTO. T/A has a 4.25” crank, the other is a 4.21”. Both solid roller cams with fully ported factory heads, should be close to 600 hp N/A. The GTO is the test mule, we hope to spray it on top of that. We have been totally swamped with projects, (guys that showed interest in trying these: sorry it has taken so long to finish this) but I started going together last week and the 2nd engine just started the machine work today.

The halo is cheap insurance. If you want to get nuts, that is what the pan rail supports that tie into the halos are for. If you can afford an aftermarket block, KOOL! This is for the other guys .

It fits in stock type aftermarket oil pans. May fit in a stock pan. Not sure how it will fit in 67-69 Firebirds. Some guys have been interested in trying just the halos. It fits all 3” engines, not just 500557s. I am not sure if it will clear the pan on aftermarket caps. I have 8 extra right now. Once I get the first engine going I will look for homes for the other 8. Then if it does what it is suppose to we will offer them to the public.

[BLACKGP]

Originally Posted by Jay S

https://butlerperformance.com/i-2553...tegory:1234783

Butler’s rate there 500557 short block assembly for up to 500 hp with a 3.75” or a 4” crank......BUT

I called Jim Butler and asked him about what they recommended. He told me 350 HP mild street build with up to a 4” crank. He seemed fairly comfortable with 400 hp, after that came the qualified reluctant answer. Maybe he is a little more conservative than his kids.

I probably should have listened to him.


We have 2 500557 builds going on. (First is like Paul K number matching example)... One in my number matching 77 t/a and the other in our 68 GTO. T/A has a 4.25” crank, the other is a 4.21”. Both solid roller cams with fully ported factory heads, should be close to 600 hp N/A. The GTO is the test mule, we hope to spray it on top of that. We have been totally swamped with projects, (guys that showed interest in trying these: sorry it has taken so long to finish this) but I started going together last week and the 2nd engine just started the machine work today.

The halo is cheap insurance. If you want to get nuts, that is what the pan rail supports that tie into the halos are for. If you can afford an aftermarket block, KOOL! This is for the other guys .

It fits in stock type aftermarket oil pans. May fit in a stock pan. Not sure how it will fit in 67-69 Firebirds. Some guys have been interested in trying just the halos. It fits all 3” engines, not just 500557s. I am not sure if it will clear the pan on aftermarket caps. I have 8 extra right now. Once I get the first engine going I will look for homes for the other 8. Then if it does what it is suppose to we will offer them to the public.

Jay S... Can the full block girdle be made to fit the Pontiac 301 T block? If so, will you offer availability and pricing info in the future? Thanks.