Hi,

I am based in the UK and have have a magnum 27 (approx 1976). It has 2 small block chevy engines - raced modified and approx 400hp each with Bravo's. Max speed is around 65mph. Problem I have with these engines is reliability, I am looking for a solution to get high 70's with some form of reliability. It seems that alot of you guys are going for single big blocks....

All suggestions welcome.

Hi,

here are some pics of the boat in question...

Supercharge them!!!! I put a 650 horse bbc in a 27 mag sedan,a boat a little on the heavier side,went 70 the boat wasn't set up properly,the drive to high,but alot of work to convert it! If you don't want to supercharge it,Try NITRUS tripps

My 27 sport has twin 320 EFI mercruisers and does 66 on GPS........maybe you can find more speed with prop work?

Otherwise....there are some guys running single big blocks that see the kind of speeds you'd like. A single engine would be potentially less trouble as you suggest.

Nice looking Mag BTW.....

Aaron

What are the problems with the engines?
I have small block 350's that produce 400hp and have good luck with them.
Good looking Magnum!

I don't htink you are gettinhg 400 hp per engine. If the boat were propped correctly and the engines were making 400 hp it would run an honest 72-74 mph.

What are the engine(s) specs?

Great looking ride!

Hi,

do you have the contact details of any good small block engine builders??

Geoff

We have two 27's. One with TRS and 350Hp small blocks runs around 62-65mph. THe second boat has stock 260's with alpha drive and runs in hte 50's. P.M. me and I'll try to help you our. I can see some changes you need ot make right off.

A>B>

I have a 27 Sport with 350/450hp Bravo (not running yet.) I expect a lot better than 70mph with 900hp. I am thinking of going 3" high at 34" side by side crank line centers. The speed calculator on BAM says mid 80's. Any help you guys can give me on drive hieght and side by side centers for sm.blocks w/headers and Bravo drives would be great. My gas tanks are in the half cabin location 2-48gal. I want to carry the bow with a three blade and stay on plane at 20mph. I will be ready to cut the transom after Thanksgiving.