Iwanna928

Take your old engine out. Take the heads and have them freshened up.

Buy a 4.7L shortblock. Check bearings and rings. Freshenup the shortblock(rings are cheap on the 4.7L)

Take your topend w/ CIS and bolt it on the shortblock! DONE EASY!

Now take the time and money you saved, do your exhaust w/ some headers and something of your choice that flows well(duel or single)

If you wanted you could buy a set of cams and make more power too!

Why complicate it. CIS works well, it's all there, 4.7L block you do not have to notch the pistons and do all that machine work etc. No wiring electrical stuff to play with, trying to get it to all work together. YUCK!

Go-carter

Thanks Shortblock, what does it mean? Pre 83, or what?

Iwanna928

Shortblock, block, crank,rods,pistons.......(minus topend,heads,camtowers,cams).Freshen up your heads and put them on your new shortblock. Rering the pistons, check your bearings, you can also do the main seals full gasket set etc.

Any model year 4.7L bottomend(shortblock) will work! If I am wrong someone will chime in! You should be able to buy a shortblock cheap.

With a 4.7L, freshened up heads,euro cams from a S2 and headers she will run very strong! Very Strong!

Go-carter

Ah, thanks. So, the heads are interchangable. Will fit the 4,7(though I might loose some power due to smaller channels, can be fixed by either porting and/or getting hold a 4,7 cis head later)

Think I'll just pick up the 4,7 engine in two weeks, and say hello to more hp and no more oil burn!

Btw. I see it has a twin dizzy. How do I fix that? Do I just need two coils, plug&play? Or do I need one more brain to fiddle with?

Roy928tt

Dizzys are run from the cylinder head, if you are using the 4.5 heads no problem!

Cheers Roy

Iwanna928

The 4.5L heads will do fine. Clean the ports up, nothing crazy. I would buy bigger valves for the heads. Then you will have a sweet set of heads!

You can find the valves on Pelican. Or 928 Motorsports.

GlenL

The twin dizzy marks that engine as an LH-jet motor, not CIS.

Go-carter

Yeah, but my heads would still fit? Or? Sorry I'm a slow learner here, I'm used to either small go-kartengines, or a smal 4cyl motorcycle engine in my racecar. So V8 is a big jump

Should have thought about the distributors though. That was pretty obvious.

Roy928tt

I think the 4.5 heads will bolt straight onto a 4.7, yes ports and valves are probably slightly smaller but they and the accompanying CIS injection should all bolt straight on and back into your car so you can happily drive it, because that is what cars are for.

Cheers Roy

Go-carter

Soo... What headers are recommended for good performance? I recon the boat anchors that is on the 4,5 isn't excatly the best

hopwood

This is the exact swap i have done. Works great. The 4.7 block and heads will drop right in. You will need an S (not S2) intake to mate upwiththe CIS injectors. Thats the only tricky bit. Plus of course your exhaust is restrictive.

hopwood

The original dizzy will work fine. Make sure you get all the vac lines connected up properly or the timing will be horribly off. The boat anchors are a bit rubbish, whem i swapped on the 86.5 manifolds i saw a 10rwhp gain at peak power and 20rwhp gain at the very top of the rev range. This is withthe exact same setup, M28/22 engine into OB.

By the way, you will lose something. The 4.5 has a sweetness and smoothness at none of the later wngines have, and almost as much torque so is as quick in a lot of real world situations.

Joel

Iwanna928

He is not talking about a entire engine swap. Just replacing the 4.5L bottom end with a 4.7L bottomend and putting the rest of his car back together. Bingo Bango, easy peasy! Keeps things simple. Same fuel lines,Dist, manifold etc.

Go-carter

Yeah! Just wondered if I perhaps should buy some new headers, when the engine is out

Told the dude that I wanted the engine today, so guess I'll pick it up in two-three weeks.

Iwanna928

To keep it cheaper I would definatly go with MSDS headers and a single 3inch exhaut instead of duels! I have duels but if I was going to do it over I would do a single exhaust Best bang fot the buck and she will sound like she has 500hp!