I Agree with Ray,
+ ya need the arm no arm no torque!!! ( Stroke that is)
Didnt Ray say NO REPLACEMENT FOR CUBIC INCH DISPLACEMENT
AND THATS THE END

Thanks for the compliment on my Spectra guys. My boat is only
24' + built in swimstep [ 25'7" total] , so extra weight of big blocks would be a problem as the boat sits low in the back at still with sbc's.>


Previous owners had twin 383 supercharged engines in my boat ,
going 85 mph at 3/4 throttle. >


Boat wasn't setup right at that time IMO , and the boat was very loose at high speed .
It still rides high , but controlled better with props turning in and K-planes installed instead of the original Bennetts.

Quote:

Originally Posted by 4mulafastech

I have twin 6.2's in my 292 Formula. 189 hours and only one IAC problem like you. Looks like they must have got a bad batch.

Mine runs right at 70 mph. It's a bit heavier than yours at 7500 lbs. It's a twin stepped hull with a 24° deadrise.

Big blocks in either one of our boats would be A$$ heavy and we would lose rough water handling.

I love the lines of the 29 Fastech .Not too big , not too small. If had one , I'd probably keep the 6.2's and add Whipples.

I have a Donzi 22 Classic (22 feet long) with a BBC. It is what Donzi puts in almost all of the 22Cs. They handle great. IMO, BBC will work fine for a 24 foot boat. That is what I would run in a 30 foot boat, for sure. They spin less RPMs/HP. I don't think drives like really high RPMs (6K).

Disclaimer:
Im not talking about #6s or any billion dollar drive that is designed to spin 500000000 RPMs. Just the standard Alpha 1, or Bravo 1. And I know there are exceptions. I know a guy that ran an 800 HP BBC behind an alpha, and it did just fine as long as he was easy on take offs and jumping.

We had a SBC program in the early 90's. Smokey gave us some input. It seemed we could make 450 lbs of torque max. We just kept on moving the it up the RPM range.

there 13 cr 372 CI 3 5/8 stroke 4.03 bore. AFR heads 15.5 cmi runners.
I am sure we could have made more power 18 degree heads but the headers were real pricey.
In the end we made 613hp at 7200 with a marine header and all accessories. Sterling could make well in the 700's back then.
Steve

Thanks. We really enjoy the 292 and plan to keep it a long time. Not sure what I will do when it is time to upgrade in the engine department, but will probably start from scratch rather than modify the black 6.2's. The Raylar LSM-550 looks like a sweet package. Still waiting to see reports on real-world performance and reliability. I think we will see over the next 3-5 years several marinized versions of the LS engine platform.

Your boat is unique. It has to be one of the smallest boats with twin IO's around.

I went through this same question and debate when I repowered my 28 Apache. It was cheaper for me to repower with big blocks because of all the parts I could reuse. I also knew it would be cheaper to reliably upgrade power to 500hp with big blocks. Lot more upgrade options available and IMO resale was better with NEW 502 blocks. No regrets.

Good point, but your Apache is bigger than my 292 which has the integrated swim platform. Even with the small blocks and current center-of-gravity of the whole package, she tends to be a bit tail heavy. IMO light weight aluminum LS engines may offer the perfect balance. Hopefully LS packages/upgrades will be more common in the future.

One other plus regarding small block boats is the additional room to work even in an 8' beam boat. I changed my plugs and impellers last year. Piece of cake, plenty of room. Something to consider.

I still don't get where people think there is alot more upgrade options for big blocks please explain this to me.

Another thing wouldn't you want your max torque closer to the max rpm you will be running so you have the most power there to carry the boat the fastest?