chewy8000

I'm thinking about purchasing a backup motor to build up for my 81' US. I have the stock 4.5 now, but was curious what motors I should look for and what is the easiest swap. I imagine the 4.7 is pretty straight forward. How new can I go? S4 would be sweet!

The amount of money I've spent replacing parts and the head gaskets I probably could have bought a motor and dropped it in already!

hacker-pschorr

Look for a 4.7 liter vs. a 4.5. Everything is a direct swap (heads, intake, oil pan etc...) Except the 4.7 is cheaper to rebuild.

Piston rings for a 4.5 at 928 Intl are $135 per piston. 4.7 liter is $33 per piston.

s-carsgo

$135 per piston? Ouch... they must be made of unobtainium.

hacker-pschorr

When I found out the piston ring cost difference I picked up two 4.7 engines

One for each OB

chewy8000

$135! I'm definately going with the 4.7

928fan4life

How does the 4.7 compare to the 4.5? I am in the same boat. I have a 1980 and was thinking of doing an engine swap. Is the 4.7 a non-interference engine as well?

hacker-pschorr

Depends on what heads you use. 80-84 uses the same head / valve so that is not an issue. The cams in the 83-84 are a bit different, but not by much.

AFAIK they are also non-interference.

If you slap Euro heads / cams on an 83-84 that might be a valve bender.


If Anderson suddenly gets a run on 83-84 motors, I should get a cut

chewy8000

What about dropping a 32V motor in? Possible? Anyone done it?

hacker-pschorr

Possible yes - so is dropping in a Dodge Viper motor.

The electronics are very different so the swap is very complex compared to a 4.7 into a 4.5 car.

928fan4life

Can you do a straight swap to a 4.7 from a 4.5? What would need to be changed if anything? What about the electrical?

Jim bailey - 928 International

the USA 4.5 and 4.7 are basically the same engine just 95 mm bore to 97 mm bore.

scott863

what kind of performance improvement does .2 liters make?

Jim bailey - 928 International

Very little ...

chewy8000

Euro heads can make a diference correct?

hacker-pschorr

Ok, now you are getting complicated!!!!

Best N/A 16V engine combo using all OEM parts:

85/86 lower end with 84-85 EuroS upper end. I've seen quotes between 270-300 rear wheel horsepower. Lean-Louis was making 270ish rear wheel with a 4.7 lower end with Euro S upper & CIS.


Any other combination will be less

IMO keep it stock (lower compression) and boost the snot out of it.