RdRacerZ28

I had read that in the past. The problem forme was that the engine had been over heated by the previous owner. It still ran and was smooth but was downon compression and used oil. The piston rings weren't doing thier job since they had gotten hot. Since I build GM EFI stuff for a living, it was a natural decision to build what I did. I'm pretty happy with how it turned out and it'smaking torque right where it needs to. After I removed the stock engine, I dynoed it just as it came out of the boat. 218 HP and 325 ft.lbs. Pretty weak. The boat would barely get on plane and I tried 3 different props. I ran the stock engine last year to get aquainted with the boat ( bought it in feb. of 2010) and when fall came around last year I pulled the engine out. I got the engine bay cleaned up nicely and everything should look nice when it's put back together.

sprink58

Jim,

Did you tear in to the 260 yet to determine what it's problems were? Some of my old Bow Tie Buds back in Birmingham tell me that they see quite a few 350 Chevy marine engines with Q-Jets with burned exhaust valves...their guess is that the Q-Jets were being set up too lean in the beginning.

I am very interested in how yours turns out ...I am considering building a pair of 383's or 406's for my 255.

This is not a "front burner" project for me because my 260's were fresh long blocks 5 years ago and run real strong as a team now.

John

RdRacerZ28

The engine looked good over all when I took it apart, but it had been over heated twice, one time very badly. What I found was poor ring seal. The cylinders were glazed badly. When you over heat an engine, you risk the chance of ruining the piston rings. They loose thier "spring" or tension. When I dynoed it, there was a fair amount of blow-by coming from the valve cover breathers. I dynoed it to see what I was starting with and hopefully to find some answers as to the performance of the boat and that test verified what I thought. No horsepower lol This weekend I chatted with a few people with over 400 HP in front of an Alpha and they all had no problems but were fairly easy on things. So that made me feel better. The guy with the "Triple Digits" Stingray also used an Alpha.

sprink58

I think if you operate equipment with out "crowding" it you can make it last...keep it lubricated and keep it cool with out repeated shocks like hole shots and wave jumping.

The nice thing about Alphas is that if you do break one you can get another one (at least down here) for around $500....they are very popular and plentiful.

RdRacerZ28

Correct!

I emailed the dyno sheets to you.

RdRacerZ28

Just got the engine set in yesterday. Hoping to have it plumbed, wired, and fired by the end of the week.

sprink58

You'll be in the water Saturday AM.

RdRacerZ28

So...... a little over two months later, I finally had the boat out! I have a few things to work out, but the EFI is working good and the new engine is barely working. I didn't hammer on it too much, but got it up to 47 MPH @ 4400 RPM. Anything past that and the power started to fall off a little. It needs transom exhaust. This was with a 23 pitch prop. Hopefully I can get it out one or two more times before it's time to put it away.

sprink58

Not that I know for sure in your case but if you read my most recent post about power loss....you might think about checking for fuel line obstructions. I found one in mine ...removed it and got a huge boost in performance....for FREE

RdRacerZ28

There is no fuel pressure drop so everything there is working well. I measured airflow into the engine and it is starting to drop. The exhaust y-pipe and transom assembly seem to be a significant restriction at this power level. I have a Corsa Captians Call to install in the spring. Also converting to hydraulic steering.