I have two Gen VI 502 engines which are HP500 clones which are attached to Bravo drives. they have stainless Marine exhausts with water at the tip.

I would like to put these engines into another boat, this one has '88 model 454's (420 HP) with Borg Warner trannies and TRS drives. The exhaust is the standard Mercruiser/Gill high riser setup with a captain's call setup.

My questions are:

Will the Gill exhaust work with the HP500 and not be reversion nightmares? If not what are my options?

Will the accessories from the 454 swap onto the 502 and vice versa? I'd like to keep all the accessories with their respective boats and not get involved with hose routing, wiring, etc....

Will the 502 mate to the Velvet Drives?

Thanks,

Greg

P.S. The idea is to freshen the 502's this winter and then next year they get blowers.....

The bolt locations and patterns are all the same. The Gen 6 does not have a fuel pump mount on the block like the Mark 4, so you will have some minor fuel issues, assuming the 500 clones have the fuel pump on the sea water pump. The exhaust will be fine. You will need to retain the bellhousings and top mount starters from the 454's, if the wiring harness is Mercury, they should plug right in.

The 2 engines are externally identical, so everything will swap over. As mentioned, the 502 does not have a mechanical fuel pump provision, but if the 454 is using a sea pump driven pump, then no problem using it on the 502. Everything else will swap over. Just keep the flywheels with their respective engine. However, you will need to change over the drive couplers and bell housings.
Eddie

They are the same accessories brackets on a gen6 are 7/16 holes and the 88 will be 3/8 holes

Visaversa..

Thanks for the replies, guys.

I'm relieved to hear that the Gill exhaust will work with the HP500 cams. I couldn't see swapping the bravo and trs exhausts in these boats, it didn't look like it would work at all.

Greg

Won't he have a problem with his exhaust final height? I was under the impression that the TRS setups use a 2" higher riser. Won't he need riser extensions to match the final exit point of the exh?

if he uses the trs''gil" exhaust from the 420's he will not have to worrie about it..

I was assuming the transmission, bell housing, coupler, top mount starter, all accessories and complete exhaust stay with the existing TRS boat. The engines are swapped out

As Mr Young stated make sure you keep the flywheels with the respective engines, however your flywheel ring gear setup will be wrong. The ring gear for a bravo boat is on the wrong side for the TRS starter, you will need to have a machine shop turn down the flywheel and press a new ring on the other side and remove the old. I had this done on a pair of TRS motors I put in a bravo boat. I think it was $150 a pair. q