Heres the sheet from the build Mike Tkach did. It was 8.5:1, with AFR 305 rectangles. 177 Blower with 1025 BG 4150 carb. only 4.2 PSI of boost at 6000 netted 691HP. That was with a 3.25 Top pulley, would have been cool to try a 3'' top, but thats all he had.

Ealeash's build made some nice power for sure as well. Both nice upgrades from a 525sc setup.

Good job guys! Nice builds. I'm shooting for 650-675HP which seems attainable.

I was thinking about starting an "official 454 Supercharged thread".

A thread with nothing but supercharged 454-468 engines, with specific build details and results. I think there are many guys who toss their 454's aside, because they feel they cant make more than 550HP with them. I know we have at least 1/2 dozen custom supercharged 454 based builds around here.

You dyno'ing yours Rookie?

I'm gonna guess, you'd see quite a bit more than that.

Are you gonna be running single or dual carbs on your 250 blowers?

I have 4 old school Barry Grant (Holley) 950's, or 2 1050 Dominators to choose from. Probably going with 4.

The twin 950 Barry grants would be a no brainer for me

We ran 2 other combinations on the dyno as well (I'll just list all 3), here is what we did and the results:

With the stock 3.25" blower pulley
649.6hp@6200 and 625.9ft lbs tq@4200. Made 3.4psi of boost at peak power

With 3" blower pulley
689.4hp@6300 and 675ft lbs tq@4200. Made 5.6psi of boost at peak power. This is the set up that will go in the boat!

My builder had a HVH 2" carb spacer and hasn't tried a spacer on a roots blower, so we gave it a whirl out of curiosity, here are the results:
3" blower pulley and 2" HVH spacer
697.2hp@6400 and 671.3ft lbs tq@4300. Made 5.75psi of boost at peak power.

All of these results were with a Holley 1050 dominator boost referenced, jets 89/97 and 34 degrees of timing. 265 AFR's with a 106cc chamber to bump compression to 8.6-8.7:1, Bob Madara cam, morel lifters, Manton .120 wall pushrods, scorpion marine endurance rockers, and stud girdle from Bob. Changed the rectangle port intake to weiand/holleys oval port intake to match heads. It was a stock 525sc base, no changes were made to the bottom end, it was rebuilt pretty recently and is a 4.280 bore so 461.

Maybe at the end of the year. When I add my blowers the engines will not be pulled. It will basically be an intake swap for me during the week.

These are the stud girdles from Bob, they look like darts but are machined specifically for AFR heads. The fitment was good, and they are a nice piece.

I don`t wanna start a $hitstorm again but at the end of the day you told us all how the 305head is way too big, Joe and Mike are dummies for suggesting it but at the end of the day all things being equal your 265 head ended up making 40hp less and the same TQ .

Would seem to me that 305head isn`t "too big" after all.

I was a retard for suggesting that the port mismatch was incorrect and I`m glad to see that was remedied.
I would also hope you remedy the 13.5 AFR at 6300 with a 177 blower to a much richer mixture otherwise it`s going to last about 4 minutes.