502 for 7.4 liter swap?

[MahtyMaht]

Got the cracked block Mk IV 7.4 liter out, (Bravo 1), looking for a replacement. Guy says he has a Gen VI 502 from in front of a King Cobra he'll sell. My set up is thru transom exhaust with Marine Stainless manifolds. Hoping I can keep those. Aside from needing an electric fuel pump pressure gauge, am I going to have coupler problems? It looks like GM changed the crank flange bolt circle when they went to the one piece seal big block cranks in Gen V. This whole internal vs externally balanced business is worrying me too.

 

[Bondo]

Re: 502 for 7.4 liter swap?

Ayuh,... A 502 will fit where a 454 was....
An OMC will Not fit where a Mercruiser was....

The Long Block is useable, the Complete motors, won't swap...

 

[HT32BSX115]

Re: 502 for 7.4 liter swap?

Got the cracked block Mk IV 7.4 liter out, (Bravo 1), looking for a replacement. Guy says he has a Gen VI 502 from in front of a King Cobra he'll sell. My set up is thru transom exhaust with Marine Stainless manifolds. Hoping I can keep those. Aside from needing an electric fuel pump pressure gauge, am I going to have coupler problems? It looks like GM changed the crank flange bolt circle when they went to the one piece seal big block cranks in Gen V. This whole internal vs externally balanced business is worrying me too.

Um...........you REALLY don't want that 502.......... I'LL TAKE IT!!!!!!!!

You will probably need to ensure that you have the correct flywheel/coupler on it.

If it's an EFI engine, you don't want ANY of the EFI or OMC *****-fire stuff on it.

(Like Bondo said........block, pan and heads you can use. everything else will need to go o EBAY!!)


Cheers,


Rick

 

[MahtyMaht]

Re: 502 for 7.4 liter swap?

Hey, HT32BSX115, I guess I really didn't ask very well, now that I'm re-reading my post, but I was wondering if I could use my Mk IV flywheel and coupler on this Gen VI 502. And if I'm to steer clear of OMC's ignition and EFI stuff, would I have to carb the 502's intake, or use the 7.4 liter mani and carb?

PS - Am I avoiding the EFI because OMC's EFI sucked, or is it because EFI into a carb application is too big a PITA?

 

[HT32BSX115]

Re: 502 for 7.4 liter swap?

The King Kobra flywheel and coupler are different enough to probably not work on the Bravo but your 454 flywheel and coupler should work.

If the EFI system is an OMC Spitfire system, AFAIK there are no replacement parts available for them. You would be better off using a your Mercruiser manifold and carb.....It should bolt right up.


ALL of your Merc/Bravo accessories will bolt to the 502 block. Even the valve covers!


The block will be the wrong color though~~

 

[MahtyMaht]

Re: 502 for 7.4 liter swap?

Oh, well, screw the whole thing, then, if the block's the wrong color, I couldn't possibly.... {;>))
That's great news, man - This thing is starting to look do-able. Next - a complete status check on that Bravo lower - You know the one - it has .030" of axial play in the prop shaft - But that'll be another thread, I'm somehow sure, unless, of course, it's simply adjustable out, I hit the lottery, and there's peace among all men by the end of the week.........

Really appreciate the info.