Funny I haven't asked this question yet, but I am nearly ready to drop in my 1986 5.0 HO engine. WIll that engine work with the 72 c4 that is in the car now?? I remember reading that I may need a different bell?
It will work. I did the same thing. The only thing you need to change is the flexplate to a 50 oz balance 157 tooth one instead of your 28oz original one. If you don't it will vibrate like crazy. You can get them from Summit (From B&M). Make sure it's the 157 tooth and not the 164 tooth that came with late model 5.0 automatics. If you get the 164 it won't fit in the bellhousing, and the gears won't mesh perfectly with your original starter. -Corbin
perfect, thanks!! How much does it cost from summit?? which model years came with a 157 tooth in case I am so lucky to find one in the junkyard, and should I use the 72 oilpan on the 86 engine?
Hey Jeremy, I don't know if there are any model years out there with the 50oz balance 157 tooth flexplate for a C4 with the small belhousing like ours. From Summit they are $105.95, part number BMM-50239. I used this flexplate when I did the swap, and it works perfectly. You can also get one from FMS, but they are about $40 more for the same thing. As far as oil pans go, just swap the 72 oil pan and oil pickup in place of the ones on the roller. -Corbin
Yes sir as Corbin said you need to get the special replacement flex plate to meet the engine balance requirements as well as fit the C4 bolt pattern and starter requirements. The spacer plate also needs to be for the smaller 157 tooth because the 164 plate holes at the starter won't line up.
I maybe wrong here but isn't the dip stick tube on the roller engine in the pan? If so, if you use a Maverick pan on the roller engine you may have to swap the timing chain cover also. Russ
Yep, Russ is right on this one too. Another option, which I did, was make a hole in the front cover for the dipstick tube. It was a little work, but I really didn't want to swap the covers. Also if you want to run your mechanical fuel pump you need to put an eccentic on the cam when you have the front cover off. If you use your 72 distributor as well, you need a new distributor gear that is compatable with the roller cam - it will eat up the gear on it now. -Corbin
I was hoping he knew all the differences between the two engines. The old distributer length is not correct for the 5L block design. Better take a look at this and be sure the oil pump drive rod is fully engaged. The 5L oil pump to dist. dimension is different. I had to make up an EFI dist for the old block in reverse of this, due to the length difference when I done the EFI conversion on a 73 motor
I don't know what to say now..... I got the special gear which allows me to use my old distributor gear with the roller cam, and so far it has been working fine. I would say that if you got a distributor out of an 85 Carburated Mustang, you would be completely certain it would fit and work right. If you do this, you would need to do the duraspark route, I believe. -Corbin
