I tried to use the motor mounts off the 455 that came out of the Electra in my skylark. They fit, but the bolt holes were off majorly. I went to Yearone.com and they had some that were just like mine with an extra hole drilled through them. $50 each +shipping. Then I went over to the store ( I previously mentioned I run a small NAPA store ) and looked up the mounts for the GS. - No Listing - So, I looked them up for the Electra, and lo and behold, the same thing. My supplying warehouse had them, I ordered them, got them overnight with no freight charge - Retail : $28.99 each. I got them for emloyee pricing. Even better. I thought I would pass this along. NAPA's part number is 602-1149. God Bless You, Paul Strassner
Paul, You'll want to read this about changing from a 350 to a 455: http://www.buickperformance.com/conversi.htm You'll need some different frame mounts.
I appreciate the help One of the other forum members clued me in the that page already. I would like to know what allowances have to be made for a long shaft 400 though.
You don't want to use a longshaft, you will alter the pinion angle and cause premature u-joint failure and vibration.
Well it looks like I am in the market for a transmission. I am not looking forward to changing the transmission.
Remember all 1973-77 Pontiac Grand Prix models had a short shaft TH400. You should be able to locate one in your area. You will also need to fabricate or buy the correct TH400 downshift set-up for your car. It attaches to the gas pedal. See the website below for all the details. Good Luck!
Trans Unless you are building a race car the 350 tubo will run fine and save much work. I have a 69 Skylark ragtop and did the 350 to 455 swap with iriginal trans and had no problem. Also you can use the 455 steering pump in it's original location if you take the hoses to a hyd shop and have ine custom made to fit. You will be better off buying a fan shroud reproduced for a 69 GS400. Finding one in the yards is almost impossible.
this is great news I had a TH350 that I pulled out of my old 72 and had rebuilt. I always heard this could be done but I wasn't sure. I will be installing it this weekend.
Just a word of caution on the TH350, there is a reason why GM put TH400s behind big block engines. The TH350 is not designed to handle the torque of 455 engines. I would strongly suggest you have the TH350 built with HD parts. If you had it rebuilt to go behind a 350 it will NOT last. You will break the sprag gear. I have told many Buick owners about this and they say they can live with the stock TH350. Uh huh! Wait until you get the 455 in and decide to drive it more aggressively than anticipated. Will get an email back from you saying you broke the sprag gear. This happened to several members and I always tell them "Never time to do it right but always time to do it over" The cost between rebuilding a TH350 and a TH400 is minor. Good Luck and hope your TH350 lasts! :grin:
I guess you are right. If I wasn't going to push it the 455 wouldn't have been my choice anyway. I tried to find a 400 but they are non-existent in decent shape. If anyone has one within 4 hours driving time from Washington DC. Please let me know. I am going to have to run what i have until then. So, I guess I need to keep my right foot out of the radiator.
