: 1970 deville with 455 oldsmobile conversion questions!!!

11-18-10, 05:13 PM
Hi guys,
Im new here and have a project lined up and in the process of having almost every part. This is gonna be a 1970 deville convertible with an oldsmobile 455 twin turbo engine. With about 650hp; i have two questions though:
The caddy engine is a backwards block so the rear sump becomes a front sump. So i was thinking of having potter automotive create a custom one by sending an oldsmobile 455 rear sump pan and copy the flange design but use the rear sump caddy dimensions and flip it 180 into a front sump. Do you think this will work?
And qhat should i usw for motor mounts? And i heard one side steel one rubber for performance engines?
Thank you very much!!!!!!

11-18-10, 08:05 PM
I would use the solid mounts. Your pan will definately need to be custom but I would think Mondello would have an answer for that.

11-21-10, 10:56 AM
I thought the 472 had the sump in the back, unless it came out of the eldo. Seems to me you should be able to use a rear sump 455 Olds, no problem.

11-21-10, 11:23 AM
IIRC, the RWD 472/500 got the front sump, FWD 472/500 got the rear sump. RWD caddy 425 got mid sump.

11-21-10, 08:40 PM
How about some pics of the twin turbo on the olds 455 .Would love to see em .BTW what turbos are you using ??
The 425 from the toronado has the main sump at the rear and a sorta hump in the middle with a smaller sump to the front . One of those should do you .Got windage trays n all

11-22-10, 09:24 AM
Would the toronado oil pan bolt right up to the 455? Hopefully itd fit because potter quoted $1200 with the oil pickup!!! Thats way more than i expected

11-22-10, 09:36 AM
Unless i use stef's oil pans, they said $650 also but wanted about 40 different dimensions and some i was completely unsure of... But potter has the exact dimensions for the deville oil pan. Would you guys think if i had stefs use their oldsmobile 455 dimensions but 180 their rear sump into a front sump? Do you think both sump sizes are approximately the same?
Thank you!!!

And ill post a new thread when the engines complete!!

Heres the stefs oil pan:

11-22-10, 02:19 PM
Would the toronado oil pan bolt right up to the 455? Hopefully itd fit because potter quoted $1200 with the oil pickup!!! Thats way more than i expected

Can`t see why not -- outer dimensionally (block ) is the same

11-22-10, 08:43 PM
Just to clarify a few points:
'68 - '76 RWD 472/500 are FRONT sump.
Eldorado (all) are MID-sump (2 drain plugs)
'77 - '84 425-368 RWD are REAR sump. Pan WILL bolt onto 472-500 blocks, but pickup tube hanger MUST be modified.


11-23-10, 10:49 AM
So there were no other front sump oldsmobile pans that would just bolt right up to my 455 right?
Also on dickmilleracing he says for motor mounts to use one rubber one solid for performance engines, would 2 solids make the car shake bad or what is perferred best?