nwimbush

I lucked out and and found a pair of used GEN V 454's on OSO swap shop a couple of months ago. Not knowing my a## from a hole in the ground when it comes to BBC's, I planned to live with the top end until a rich relative dies, but clean up the bottom ends now, before i squeeze them into the '89 281 Maxxum.

Well, I've learned a little about GEN IV, V, and VI blocks and heads now, and found that I have a mismatch - 101114182 blocks/10114156 heads.

I also just bought a parts package - carbs intakes exhaust and (qty5) rect port 14096188 heads - these don't fit my GEN V's either, but have been reworked to 2.25 intakes and have some value.

Can anyone offer some advice or history to GEN V blocks?
From the water passage layout one might think they would be able to handle some high comp and rpm heat, but, just finding GEN V gaskets wasn't easy. Should I consider trading these for GEN IV blocks for parts availability?

Can anyone recommend a 5800-6200rpm head for these blocks? 14097088 appears to be the iron rect port replacement, but I've seen aluminum options 12363400, 12363399 as well.

Rookie

iTrader: (4)

I have a 14096188 and a 14097088 head on one of my GEN V block. (Iron rectangle heads) you should be OK.

I use Fel-Pro marine 17046 gasket

hoozeyurdaddy

gen V blocks have 1 piece rear main seal and no fuel pump mount, exactlly what on the heads don't fit, they should bolt right up?

nwimbush

The water passages don't line up and they piss water into the lifter valley according to GM - see http://www.gmpartsdirect.com/perform...CATID=361.html

"Casting number 14096188 or 6272990. Cannot be used on Gen V engines because of upper water hole alignment. Open Chamber Design." , but Rookie is the second OSO member who has told me the use of a particular gasket will enable the 6188s to work.

Well, today I got my Gen V specific gaskets from EngineTech, expecting the head gaskets to have more holes than my underwear, but there is only a couple more than the Gen IV's..

Since I've got 4 7088's on the way, I'm really curious as to how closely the head water passages match the blocks.
RPM expectation is 5800 - 6200 and i want to ensure even, parallel cooling acros the heads.
Thanks - anyone got a pic of the business side of a 7088?

Rookie

iTrader: (4)

Question I need to ask, what are your goals when all done. I see you want to spin it to 5800-6200. what HP and TQ you looking for? I liked my Merc 425's that I had with these heads. What were your base 454's: Mags? 330''s? 420's? just curious. I was fortunate to have the forged internals in my 425's and just rebuilt using a good base. saved money instead of buying an inexpensive stroker kit.

Take those heads, a good Hydraulic Roller cam and after market exhaust and you'll have some good reliable engines. and not breaking the bank. If you want to upgrade to more power later on, be patient and wait for a deal to find some aftermarket heads and your there.

I've done allot of research on what you can do with those heads and a 454 block.

nwimbush

Rookie,

My goal is to build two mills requiring me to buy a larger boat.

I found the Checkmate I've wanted for many years in September, and just the way I wanted - two Bravos w27's, K-planes, and no power.

The engines I found in Kansas and have come with Gen VI peanut heads, Gen V blocks, cast crank, but, bored .030 recently - I can still see some cross hatching and the #1 con rod bearing is like new.
The pistons are TRW L2377f forged which is anywhere from 9:1 to 8.1:1 with 118cc, dependent on where you look. I may leave these until the head work is done, as I'd like about 9.5 or 9.75:1 at the end of the day.
The parts with the engine package also included 2 Comp Cam 286H,(with 110 duration and 556 lift.) Keith E roller rockers, springs, ret,.,
I found the 7088 heads, wieand intakes/dominators, and 1 set of Gils this week - need one more - already have tailpipes.
I think they'll crank about 500hp each, what do you think?

Rookie

iTrader: (4)

sorry I didn't get back earlier, I think what your building is similar to the 425's I had. GM rectangle heads, similar cam (yours is on a 110) similar lift and duration. I think you will be around 425-450.

http://www.offshoreonly.com/forums/s...ht=420+425+cam

If you your going to build up some engines I would put the hydraulic roller cams in now while they are pulled, and put better heads on later. You will see a big increase with the roller cams, and then another big increase with better heads. Those heads will build power but you really have to spin RPM's.

nwimbush

Thanks for the response - I got Dennis Moore's book yesterday and on page 14 it confirms the head water passage layout mates with the Gen V blocks' improved head cooling design. I'm waiting for delivery now.. probably early next week.
I see your point about the roller hydraulic cams, and I'll look into it further.I don't know if the CB 286H-10 is roller-hydraulic or not (yet).
I plan to shave the heads to about 030 - I think that should drop the cc to 115 from 118 and get me closer to the 9.5:1 (with the TRW L2377f on stock rods) that the cam is looking for. Rings next. thanks for the help,

Alex

From what I've learned .. mainly from Dennis Moore's book but also from probably all available CBB related books ... some Gen V head castings may be used on Mk IV blocks but with great care and with matching head gaskets.
From Gen VI the situation is said to be a little better due to more material around the cooling ports but still not a satisfactory combo. I also thinks this statement relates to the block side of the parting line, since I have found no info that the 088 head has been revised.
Any experiences around this matter will be appreciated since I'm currently rebuilding a 454 Mag Mk IV for a customer.

Rookie

iTrader: (4)

It is not a roller cam. Those heads do not like heat and are known for cracking between the seats. I am no engine expert but I would run a cold thermostat or a flow restrictor and keep them cold. I learned the hard way this season. One engine had thermostat with holes in it and always ran cool, the other didn't and always ran warmer. It cracked between the seats, and dropped the seat through the piston. It was some self inflicted I knew it was getting warm but the gage only said 190*, but I was running hard with tabs dropped in some rough water laboring the engine pretty hard.

http://cgi.ebay.com/ebaymotors/COMP-...spagenameZWDVW