SB

iTrader: (1)

Greater the rate of fall the less chance of reversion. Some boats with side exit exhaust and some boats with s pipes that locate tips under swim platforms (think Eliminator boats) usually take more camshaft for the same exhaust.

cyrus77

iTrader: (4)

Hello, I have built several MPI engines and have lots of parts left over from my build.
I have bored out throttle bodies 68 MM https://www.tpis.com/pages/11_7_12
Ported upper intake to match throttle bodies
Cut down intakes for higher RPM.
Extra wiring harness
MEFI computers
Cool fuels
distributors
etc

cyrus77

iTrader: (4)

Also adding more timing is a big benefit to these motors as they have only 28 total degrees of advance.

Diamond Dave

PM sent.

cableguy1979

Chattanooga, TN willing to drive for the anything that will help if its not on the other side of the country. I have located and purchased a 10114182 Gen V block which is the exact casting of my original block. I have my factory forged crank magnafluxed and he said it was cracked everywhwere. I havent taken the newly purchased engine apart yet but it came from a 3500 automatic dually. Im hoping for a forged crank but its proven to be a very rare option in any gen v 454. Im banking on the crank being good. If it is cast does anyone know if this would be a cast steel or cast iron crankshaft? If its cast steel Im going to use it with my pistons and rods. If cast iron ill buy a scat cast steel crank and again use my rods and pistons. Has anyone ever tried running a cast steel crank in a 454 or 502 mag mpi? Supposedly rated for 700 hp.

I do know if i go cast steel i have to run a different flywheel and harmonic balancer since my crank was forged but those should be pretty common and cheap.

cableguy1979

is this the cam flat tappet cam for the 454 mag mpi?

phragle

iTrader: (3)

if yours is a mag, it came with a forged crank...the nonmag 7.4 had a cast crank.

cableguy1979

I know mine is forged as stated in my post. The new engine I bought is cast crank. Yes im considering using the cast crank in my mag engine. The mag really only has 60 more hp than other marine 7.4's on a cast crank and i can't be the only one who've tried this. I can't see 60 more hp breaking the cast crank. I'll use the mag pistons, rods, cam, intake but use the cast crank
10114188 which I believe is the stock crank in a merc 7.4 mpi.

phragle

iTrader: (3)

A merc cast crank is pretty safe as long as you keep it under 450 hp and 5000 rpm, and as long as you dont drive a boat the way I do.....

But just so we are crystal clear on what happens to a cast crank when its not happy with your build...







.

liberator221