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-   -   400 hp efi small blocks?? (https://www.offshoreonly.com/forums/general-q/56460-400-hp-efi-small-blocks.html)

Iggy 08-08-2003 12:17 PM

The Holley ProJection Marine system sells for 2400 at CP Performance, less manifold. Bolts to any 4bbl intake.

mikev 08-08-2003 05:52 PM

thats what i need for my 19' donzi the thing would fly with that motor. considering i can run 50 with my 4.3 v6

bobl 08-08-2003 09:49 PM

I recently built a very nice EFI 6.2 for a customer. The Merc MPI system is pretty well maxed out as it is. We swapped it for an aftermarket system similar to the Holley Commander 950 and used a FAST ECU with wide band 02 sensor & 42 lb. injectors. We ported the Vortec heads, added larger valves and upped the cam just a little bit. It was a bit pricey because of the high end electronics, but the results were worth it. He gained 8 MPH over the stock 320HP engine, so it was certainly producing well over 400 horsepower. The engine started easier than stock and we were able to tweak the idle A/F ratio to where there was no black transom at all.

nauticaL ILLUSIONS 08-09-2003 10:19 AM

Alright CAT, join the elite club of big block ass kicking small blocks. I have a pair of SBC bored to 358 and apparently putting out 420HP which I don't question for a minute. I never had them Dyno'd but the summer I had them done I ran the 1000 islands poker run and was balls to the walls the hole day and ran dead even or 1-2 MPH faster then a New Pantera with twin 502MPI's and I had 5 people in my boat and he only had 2. I think they're definitely putting out some ponys and very reliable to date. Its been 3 years. This winter I'm considering putting big monster 8-71 blowers on them dialed to around 6-7 PSI to give me around 575HP. I'm not sure if that boost is possible without intercoolers. I'm hoping by using huge blowers they won't have to work as hard to raikse the boost hense lower intake temps which may not require intercoolers but I'll have to do more research. I went online to a supercharger site with all the calculators and it said with my HP and 10PSI with a 2 core intercooler I would make 712 HP at the crank. Holy **** was my response. We'll just have to see whats in the cards for the future, but I'll tell you one thing, I LOVE MY SBC's.

fishead 08-09-2003 03:02 PM

If the motors are set up right 5 to 7 lbs is no problem without a intercooler.My Troy Dennis small blocks are dynoed at 785hp each and they are set up for 9 lbs without a cooler.I never see the 9 lbs usually just around 5 but I am still breaking them in.I am probably going to put intercoolers on next season.They are Donovan Aluminum blocks with Pontiac aluminum heads Jessel shaft Roker system dry sump oil system and B&M Megablowers.They have all the best internals and that is the key.The motors really are sweet and start right up and idle just fine with a little blower lope.

fishead 08-09-2003 03:02 PM

If the motors are set up right 5 to 7 lbs is no problem without a intercooler.My Troy Dennis small blocks are dynoed at 785hp each and they are set up for 9 lbs without a cooler.I never see the 9 lbs usually just around 5 but I am still breaking them in.I am probably going to put intercoolers on next season.They are Donovan Aluminum blocks with Pontiac aluminum heads Jessel shaft Roker system dry sump oil system and B&M Megablowers.They have all the best internals and that is the key.The motors really are sweet and start right up and idle just fine with a little blower lope.


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