Advice please for rv8 4.6 swap

[UncleThunderpants]

Hi, I have bought a secondhand 4.6 that I intend to strip down and check over ( pressure test etc) which I intend to then put in my escort that currently has a 3.5. The car is a lt77 box, 3.5 with 390 holley which has possibly had work done to it before I bought it as it put out 201bhp at the flywheel on the rollers. I also realise that I need to swap over the sd1 water pump and timing cover/sump from the current engine also re-jet the carb and change the cam ( to drive the dizzy). Soooo,,,

Has anyone any advise on which cam I should go for?

what power jump could I expect from a 4.6 over the 3.5?

Any other advise on this would be appreciated, thanks.

[sidecar]

Hi, I have bought a secondhand 4.6 that I intend to strip down and check over ( pressure test etc) which I intend to then put in my escort that currently has a 3.5. The car is a lt77 box, 3.5 with 390 holley which has possibly had work done to it before I bought it as it put out 201bhp at the flywheel on the rollers. I also realise that I need to swap over the sd1 water pump and timing cover/sump from the current engine also re-jet the carb and change the cam ( to drive the dizzy). Soooo,,,

Has anyone any advise on which cam I should go for?

what power jump could I expect from a 4.6 over the 3.5?

Any other advise on this would be appreciated, thanks.

I run a piper 285 cam, stage III heads etc on my 4.6, it knocks out around 300 BHP at the fly. With standard heads I guess it might knock out 230-250 BHP. I replaced an old knackered 3.5 with the 4.6 lump. My LT77 box did not last long behind the new engine.

The BHP figures don't tell the whole story, my car is much more relaxing to drive at low RPM with the bigger engine, it pulls in any old gear. When I boot the throttle the car takes off. (I've bunged on a 85 BHP NOS shot just to help it along)

[ChrisJC]

I'm running a Piper 270 on my 4.6. It has lightly ported heads, Range Rover EFi cast exhaust manifolds and twin 2" SU's. Megajolt for mapped ignition, and it chucks out about 250BHP at the flywheel.

Chris.

[Denis247]

You may need to 'dress' the sump to give clearance for the longer stroke of the 4.6.

Also a spacer behind the front pulley.

I'm running a Real Steel 416 in mine, but you'll need to fit shorter/shorten the valveguides 0.1" and use special springs for clearance at full lift. Also tried the 'Stump Puller' but the 416 revs better and the 4.6 isn't short on torque.


I used a rejetted Holley 390 with Offenhauser 360 manifold for a time and it worked ok, but the 500 Webber is really the way to go.

[UncleThunderpants]

Thanks guys, some usefull info there, and I have more idea of the bhp I can expect (250 ish)