bck

I've got two problems going on here.
1- Took my motors to an engine builder. Didn't know of him personally, but took a knowledgeable friends recommendation. He is a couple hours away. The motors are Mk IV 454 bow tie blocks complete. The motors froze from not being drained after removal from boat. I thought having all coolant lines disconnected would be good and I am used to a heated warehouse, but the one I was working in this time was not. Popped a couple freeze plugs. I made the builder aware of this. He said he would not look at them for a couple weeks, then called me back a couple hours later telling me that he removed the intakes and both blocks were bulged out-the steel was bent, not cracked, in the lifter valley area. Does this sound like the type of damage that could occur from freezing ? I wouldn't have been surprised by a crack, but bulged out in the lifter area and still able to be spun by hand? I know at least one of the motors turned over by hand. How do I know this guy isn't just trying to score a nice set of engines from me? I guess I need to hop in the car ASAP and go check it out personally ?
2- If they really are junk, what is the best route to go with replacements as far as accessories? I don't want to replace everything bolted to them. Are all external bolt ons interchangeable from Mk IV 454 to modern 502 ? Is there a best choice for parts interchange? As far as the power I am looking for I would be happy with a minimum of 500hp, 600 max.

mopower

You could go with Merlin blocks. They are interchangable with MarkIV. Late 502's do not have a mechanical fuel pump boss and must change the seawater pump to accommodate the fuel pump or change to and electric fuel pump(which I feel is too trouble prone)

bck

Would that be a 502 and higher Merlin ? I assume they don't make a 454. I would like to reuse as many of the accessories as possible. Oil pan, bell housing, alt, power steering, the Merc distributer, starter, pulleys crankshaft mounted sea water pump-the kind that is bolted to the center of the crank and spins with the crank, the brackets that held the fuel and oil filters etc. I would prefer mech fuel pump, but would go elec if I had to. What about head and intake compatibility ? Again I would be looking for 500-600hp.

PatriYacht

I would go to see it for myself. Is it a visible bulge or something he measured. Unfortuately he has a lot of incentive to tell you the blocks are junk. He sells you new ones and gets to keep the old ones. Always have to be wary.

MarkSmith

MRD is a reliable house in New York area.

Mark

cstraub

GM blocks are very prone to busting and cracking in the lifter valley area. This is common. The engines still would turn over.

Merlins are good choices but you can still find Gen 4 blocks that are good cores in the junk yards. We use to buy them for $100. All your parts would then be compatiable for sure.

Chris

bck

I'm gonna take a ride and look at them, probably just being paranoid, but I'll sleep better. Now what to do about replacing them. Check to make sure the rest of the parts are ok and just get some new 454 blocks, or scrap it all and start with something different.

JJONES

If Money Was No Object,buy Everthing New ,then There Is No Guess Work Or Paranoia!but Money Is Usualy An Issue So I Would Find Some Good Cores,take Everything Off My Old Ones From Crank And Pistons, Have Everthing Inspected And Magnifluxed,replace Only Whats Needed,have The Blocks Youve Found Line Bored,honed And Decked And Put Everthing Back Together ,might Be A Little More Labor But Thousands Less In Parts!OH YEH,I WOULD BE AT THE SHOP YOUR ENGINES ARE IN AND INSPECT EVERYTHING,AND HAVE THE BUILDER SHOW YOU HIS MEASUREMENTS AND COMPARISONS WITH OTHER BLOCKS!

bck

How about this. I go middle of the road with that idea and get either Dart Big M or Merlin III blocks, which are completely compatible with all my MK IV stuff and punch them out to the max bore 4.65 (or close to it)and use all the old stuff I have that is still good. That way I can use all my old external stuff and probably my crank and get a larger cid because of the increased bore. Sound good or not? I will check my blocks, I do have the casting numbers and would probably recognize them anyway, if the damage is not visible to my eyes or seems questionable I will leave with them to have someone else look at them. I think the guy is honest, but you never know. He works for a shop that builds motors for big name people, he is doing mine on the side. I would like to mention names to get a response but I will not do that publicly, as I think I have portrayed him in a negative light without proof and it would not be fair to him. If he is screwing me everyone will know his name. My original budget per engine could have gone as far as 5k but he felt he could do it cheaper than that. So, does any one have a plan to get 500hp for 5k now that my blocks are shot.

bck

I agree that getting some old cores would be the cheapest route (money is a concern). The problem is finding a pair of Mk IV blocks, hoping they are good, taking them to a machine shop to have them checked out. Then still having the same probs with trying to get 500 hp out of 454s (that was my original goal, and I would still like to reach that level) and having lesser quality blocks than what I started with. Just plain sucks, although spending 2k per block from Dart just to get another 454 block isn't my idea of fun either.