I am at the stage of mocking up my 425 to fit into my 56 Special. I have a rear sump oil pan and will modify the engine mounts to fit, using a combination of 425 and 322 mounts as suggested by Tom Telesco, or something similar. I will photograph and document the process as I go for future reference. The engine currently has the 65/66 straight exhaust manifold (pic 5) fitted and there is virtually no clearance around the steering box, (pic 3) with the engine centred on the crossmember. I plan on upgrading to a new GM Delphi style box and am unsure as yet on its dimensions. http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=160591779046&ssPageName=STRK:MEWAX:IT How much clearance should I have between the steering box and exhaust manifold to allow for torque twist and any heat transfer? Should I be looking for another manifold, or just offset the engine slightly to the passenger side? In an article posted on The Hamb by Tom, he suggests using a 59 manifold. Can anyone who has done this conversion give me the details of exactly which one I need as I will need to find an import one to NZ. (Pic 1) Adam Martins 58 manifolds look like they may work? I dont really want to fabricate headers unless I have to. The pictures I have of 59 manifolds dont appear to make the fit any better. (Pic 2 & 4). Any advice appreciated. Thanks Ross
You might mill 3/8 of a inch from the exhaust manifold head mounting surface...and a simple heat shield of sheet metal slipped between the manifold and the steering box will work wonders for cutting the heat.... then consider this , when the engine torqs it is going to move up and to the right away from the box... you can limit the movement by a piece of chain/cable/or bolt thru the motor mounts....You could mill some from the side of the head too.... and how much clearance can you get by raising the engine up?????
:TU: Thanks Doc, great ideas. I will try and lift the engine a fraction and if I still have clearance issues I will mill the manifolds. Thanks Ross
I wouldn't mill 3/8ths. from the manifold it will make it too weak & not seal. Don't forget Buick used NO gaskets on the exhaust. If the manifold you now have clears the back i would mill an 1/8th. from the flanges. Like Doc said the engine will torque up & to the right creating more clearance. Tom T.
Yep,,, 3/8 was just a swag measurement... maybe 1/4,,,, and I was turning this thing over in my mind,,,, could the steering box be moved any at all???? I thought of milling, say a 1/8 or so off the mounting surface of the steering box to move it outboard some.... you dont need much clearance.... if the flanges are ,like 1/2'' or more thick that might be a option to or a combination of both....i did see a car once that had the steering box moved over by cutting the mounting surface out of the frame and rewelding it ....
That's another good idea Doc. Looks to be an 1/8th. clearance now with NO mods. 1/8th off the manifold & another 1/8th. off the mounting surface of the box & now you have a minimum of 1/4". More than enough.
Find a 1957-58 Buick 364 left side manifold. Used one on a 53 Mercury swap and it raised high over the steering box. May need to check on the difference between dual and single exhaust type manifolds. I have forgotten which one I used, but one goes UP above the flanges.
thanks Gary, Thats probably like the one in the first photo of Adams 58 364, seems to have a higher rear end. Ross
Ross, What did you ever end up with for the manifold solution to clear the steering box? I have a similar situation and am currently using a 322 dual exhaust manifold on the left side of a 401 motor. I don't have any exhaust leaks but the round/rectangular exhaust port match up does bother me. Thanks, Steve
Hi Steve, Unfortunately I cannot give you a definite solution but it looks like I will get the clearance by lifting the engine slightly on the mounts. Still only tack welded. The Buick project has been on hold due to other projects and commitments, and helping my wife set up a new business as well as a full time job. I see Russ Martin has a single and dual exhaust 57 / 58 left side manifold which should work. http://nailheadbuick.com/exhaust As I mentioned early on I will photograph progress and document when I have definite results.
I would also consider the purchase of one of Tom Telesco's mini starters. If nothing else, it will save weight and make access easier. I have one in my 425-powered Chevy pickup, and although there is room for a standard starter, I needed a new/rebuilt one anyway. I was able to use the stock '66 left side exhaust manifold (actually, there is better clearance now then there was with the stock engine - a 6.2 Diesel), but the extra room is great, and I don't need any heat shields.
I have one of Tom's mini starters, but the tight squeeze is around the steering box. I have access to a 59 single exhaust as well as a 63 manifold but looking at them it just doesn't look like they will quite fit. I was hoping somebody had a real life fit I could duplicate. Looking at the pictures in the first post, I might try the 63 manifold with a little milling off the face. I was wondering about shifting the motor a 1/4" or so towards the right side with a spacer on the motor mount. I wouldn't think that would put things out of whack too much on the drive line. Right now I am entertaining all ideas.
Hey there my 425 is being rebuit as we speak .......I knew of this problem awhile ago. I have my Frame all ready for the motor and tranny ........I have bought a driver side exhaust manifold from a 1958 buick I will let everyone know how it works out for me
