Gen V 454 MAG EFI heads and intake on Gen VI 7.4 MPI block

[Mischief Managed]

Found a reasonably priced 454 MAG EFI gen 5 donor motor with a cracked block that I am thinking about purchasing so I can use the heads, intake and ECU with my Gen 6 block. Despite "EFI" on the decal, it appears to be an MPI motor with 8 injectors. It looks just like a 454MAG MPI on the outside. How difficult would this project be? I'd like to keep the serpentine belt and fuel pump from my gen 6 motor. Will the gen 5 forged crank fit in my gen 6 block? Might go with a 496 stroker kit regardless... Might have a fun Winter project.

 

[tpenfield]

Wouldn't the heads be suspect if the block was cracked?

 

[Bondo]

Ayuh,..... Both the heads, 'n intake are probably cracked as well,.....

 

[Scott Danforth]

I would suspect if the block cracked, so did the heads and intake

FYI - Gen VI block is better than the Gen V internally. both available at your local salvage yard cheap (look for 2500 and 3500 trucks - 1991-1995 for gen V, 1996-2000 for gen VI)

crank is the same, however its most likely a cast crank. the 502's and HO motors were the ones that got a GM forged crank

heads would be suspect. the L29 heads oval ports on the later gen VI motors are better flowing than the peanut port heads on Gen V. Gen V heads fit gen V blocks unless you get the rectangular port heads as those were originally designed to go on the MK IV block as well.

better flowing heads out there for the BBC depending on budget. Merlins are a great upgrade

if you are going to build a stroker, stay away from Eagle parts. Scat is a much better off-shore product than Eagle and that comes from my machinist

 

[Mischief Managed]

I would suspect if the block cracked, so did the heads and intake

FYI - Gen VI block is better than the Gen V internally. both available at your local salvage yard cheap (look for 2500 and 3500 trucks - 1991-1995 for gen V, 1996-2000 for gen VI)

crank is the same, however its most likely a cast crank. the 502's and HO motors were the ones that got a GM forged crank

heads would be suspect. the L29 heads oval ports on the later gen VI motors are better flowing than the peanut port heads on Gen V. Gen V heads fit gen V blocks unless you get the rectangular port heads as those were originally designed to go on the MK IV block as well.

better flowing heads out there for the BBC depending on budget. Merlins are a great upgrade

if you are going to build a stroker, stay away from Eagle parts. Scat is a much better off-shore product than Eagle and that comes from my machinist

The cracked engine is the 385 HP MAG version of the 454. It has rectangular port heads and a forged crank. That's why it appeals to me. I would use my current gen VI 7.4 MPI block with the heads and intake for sure since I prefer the roller lifters and it's supposed to be a more robust block than the gen V.

I cannot find any data on cracked big block intake manifolds and heads from freeze damage online. That makes me think it's not common. All the stories I see are about cracked blocks and exhaust manifolds.

 

[tpenfield]

Probably no real data/info on cracked blocks vs cracked heads, because once the block is cracked folks don't look much further into the engine and just go the long block route. So, it is a roll of the dice salvaging parts from an engine w/ a cracked block.

 

[alldodge]

The 454 MPI (385hp) use 502 heads (rectangular port) that's how they got that much hp

 

[Scott Danforth]

its the GM 088 head
14097088...91-up...rect...OPEN...Gen.V 454/502 HO, 118cc chamber they have 316cc intake plenums here is a good read on airflow, etc. http://www.superchevy.com/how-to/project-cars/sucp-1208-big-block-heads-shootout-the-o-vs-r/ 088 head flow from superchevy Flow Data: CFM @ 28-ins Stock 088

Lift	In	Ex
0.050	32	27
0.100	77	56
0.200	144	112
0.300	206	142
0.400	245	166
0.500	289	188
0.600	320	192
0.700	334	197
0.800	335	201

Merlin 269cc oval ports will out flow them by 30CFM, the Merlin 320cc rectangular port will out flow them by up to 40CFM


https://www.billmitchellproducts.co...l-bind-1-150-max-lift-650-assembled-each.html

World Products MERLIN 310cc Iron Head Flow Data

Valve Lift--.300 --.400 --.500 --.600 --.700 --.800

2.300 ----- 213 -- 275 -- 323 -- 363 -- 383 -- 374
1.880 ----- 165 -- 204 -- 239 -- 262 – 276 -- 286