Donzi hornet3 repower to 502 questions
 

I?ve got a 1986 hornet 3 with a very tired stock 454 330hp that I?m replacing with a gen V 502. I?ve got a TRS drive with borg Warner.

What swaps over?
Can I use the 454 exhaust manifolds?
Can I use the oil cooler, alternator, raw water pump etc from the 454.
it has 3” through hulls, is there anything to be gained by going to 4”?

Any advice would be appreciated,

those blocks are the same, all of it will swap over, no gain from 3 to 4inch in a stock configuration

Gen V no manual fuel pump provision. Some bolts on the heads for accessories go from 3/8 to 7/16, no big deal.

Not sure if gen 5 is a serpentine set up or not. If it’s not , a water pump with fuel pump boss can be used . If it is you may need a stand alone electric fuel pump , which is no big deal. Everything else will bolt right up. If the manifolds and risers are original 1986 mercury may want them for their museum 😂

The manifolds are original:)

Gen V is V belts, so get a seapump with a mechanical fuel pump or switch to an electric fuel pump

Replace the 35 year old manifolds and risers and go to 4"

Pics!!

Make sure to use the correct flywheel for the 502. Different balance for MK4 to Gen 5 & 6. Even cast and steel Gen6 cranks use different flywheels as far as balance goes.