articfriends

iTrader: (1)

What do you consider a "high hp" 540 when it comes to procharged? I made over 1100 hp from a 540 blowing thru a highly modded mpi intake w procharger and several variations of less power thru the years. most important questions:
1. what block
2. what exhaust
3. what heads do you own or plan to get
4. what model procharger do you have
5. whats lowest octane gas you will run

c6silver

Thank you for taking the time. To answer your questions
1. 502 bored .030
2. Up in the air, but NOT stock Merc. Gil, Dana, KE (IF I can find a set)
3. currently GM 088s but open to suggestion (have aluminum Pro Comps but would rather iron for durability)
4. Not purchased yet, want to run the boat N/A at first
5. 93 is fine by me (10% ethanol here in the NE)

articfriends

iTrader: (1)

So, if you mod the intake, buy appropriate injectors, build a stock block 540, use factory iron heads touched up a little, no reason why you could make a legit 600 hp/600 ft lb tq NA 540. That would put your 25 outlaw in mid 70s assuming you haven't gutted boat, put on extension box, shorty, etc. Then boosted with m3 procharger at 7.5 lbs of boost would put you at about 800 hp accounting for parasitic loss of blower and into the low to mid 80mph. Stud the mains, stud your heads, MLS, etc, keep turning boost up on dyno till you get to the 800, 850 range and call it good with your stock block, somewhere past there you will have main cap problems, IMO, others may say they use stock production block at 1200 hp, I would NOT. I do flow, clean and sell injectors, modify intakes and throttle bodies, dyno, tune and build engines so If you have any questions, feel free to ask or pm me , Smitty

c6silver

I sent a message to your shop already asking more or less the same question, and I WILL be using your services for sure, thank you so much !

PS The whole impetus for this exercise in excess (lol) is a friend with a 40 foot Baja Outlaw with triple supercharged 540s, he says it runs mid 80's... so it would be nice to at least be in the ballpark.

c6silver

OK, I'm not going to lie...the idea of being HP restricted by the stock 502 block didn't sit well with me, so I went and ordered a World Products Merlin 4 tall deck 4.600" bore block, so with my current parts a 565 (instead of 540) is in the cards (have intake spacers), so now that leaves out the GM heads, I have a few options. Merlin 345cc cast iron heads, or a set of 360cc (that seem to run 369-370 in actual practice) Pro Comp aluminum. What say you ? (I don't have enough posts yet to send PMs, sorry)

xlint89

Heads in the swap shop

Dart iron eagles 345`s

c6silver

Smitty, any ideas on what parts to use for a Merlin 4 565 with Merlin 345cc heads ? The eventual endgame is to run M3 Procharged, but is the EFI the way to go ? My boat IS NOT EFI from the factory, although I have considered making the swap, BUT if the engine will make more HP with a carb (I have a big GM single plane and a 1200cfm Dominator ready to go) OR convert the single plane to EFI I'm willing to discuss best options...
Thanks !

c6silver

Oh, the cam I'm planning to use is a Crane solid roller 246/254 @.050, .615/.636 lift, 114 CL, but maybe bumping the lift .030 with 1.8:1 rockers... will this cam be prone to reversion of water into the exhaust ? Seems tame for a 565 (if it were in a car that is).

articfriends

iTrader: (1)

Where are you adding water into your exhaust at, that will determine reversion with your cam choice. You have lots of duration, obviously your not going to run sock iron exhaust manifolds witha 565?
Heads: earlier you mentioned Pro-comp, chinese junk that will fall apart and wreck your engine.
Merlin Iron 345's, terrible, low flowing exhaust port in stock form, uses same ex ports as the 310, barely flow more than stock rectangle port factory heads. Have NEVER been impressed with merlin iron heads in general as far as power goes (without quality port work), any particular reason you chose them?
efi vs carn comes down to money, any efi sytem that uses a Knock sensor and port injection is going to be pricey. Holley does make a TB kit with dominator style tb with injectors in TB and extrenal ecm with knock sensor, I used on on a 565 bbc recently along with coil on plug and made over 900 hp NA so it wasnt holding it back by any means.

c6silver

Goddamn it I’ve typed this reply THREE times and keep getting logged out before I’m finished !!! WTF ???

Exhaust is TBD, but won’t be stock.

ProComp heads are completely bare castings that even the guides are out of, if the castings are good enough I could rebuild with good parts…

Merlin heads are the only cast iron heads available due to supply chain issues. I’m happy to pay for QUALITY, DOCUMENTED (flow bench tested) porting.

Cam is unused left over from my 540 69 Camaro build, but 246 @.050 doesn’t seem like a big cam for 565 CID, not in a car anyway.

I have a 502 MPI complete setup and intake spacers for the tall deck Merlin IV block, so I could do that, single plane Dominator carb or single plane EFI, whatever the best choice is.