4.5 V8 EFI/CIS interchange
 

While working on the SL that's currently making me nuts....I went out and looked at an old (Michigan Rustbucket) '73 SLC I've got. Are the injector holes in the cylinder head the same on the "early" EFI 4.5's and the "later" ones with CIS?

Is there a difference in the EFI and CIS 4.5 that prevents interchanging them, assuming that you do it correctly, and switch everything?

To "cut to the chase"....I've got a sweet-running 4.5 in a '73 450SLC (with 88K actual) that you can literally watch the road go past under your feet......and a gorgeous rustfree '79 450SL with over 200K.

Thanks for any/all input!

Jim Steere
Everything Automotive
Crystal, MI
(989) 235-4000
www.usedbenzparts.com

In theory, K-jet can be retrofitted with D-jet. Not 100% sure on cylinder head compatibility but if not, you can take off the cylinder heads from the SLC and put them on the SL. Alternatively save time and effort by replacing the whole engine. Also, you'll have to change other components including fuel pump assembly, the D-jet computer and its wiring, etc. You may be better off getting a K-jet 450SE or something similar and sourcing an engine from that.

Adam
'77 6.9

4.5 interchange clarification...
 

I guess I didn't clarify what I had in mind.....sorry... I'm trying to figure out if I can put the low-mile '73 SLC (EFI) engine in the '79 SL (CIS) using the original CIS F/I, etc for the car....in effect, keeping it all original and correct....using the '73 "long block" assembly only.

Jim

You will have to swap the heads, the holes are different. Block is identical.

Peter