ejw71 Posted March 6, 2002 Share Posted March 6, 2002 Rather than reinstall the SB350 and later replace it with a SB400 I've decided to install a SB400 now while changing the TH350 to a 700-R4. Concerning the SB400, I must drill non-400 heads for steam holes, use SB400 harmonic balancer and flexplate. Am I forgetting anything related to installing a SB400 where once rode a SB350? Tks. ------------------ Ed '71 Black 350/700R4 Mar. 31th completion date '71 Saddle SS454 orginial '71 Project, 2" chop planned Link to comment Share on other sites More sharing options...
Grease Posted March 6, 2002 Share Posted March 6, 2002 EJ i think you got it all.when you get the 700 in just be sure to adjust the cable correctly. and you will need a shorter drive shaft. i made a braket for the rear mount so the crossmember would fit some existing holes. i havent yet got my parking brake cables situated. mike Link to comment Share on other sites More sharing options...
alex's72fgmc Posted March 6, 2002 Share Posted March 6, 2002 you might need to change out the engine mounts and shift the crossmember back a few holes as well. the 700 r-4 will require a shorter drive shaft and posible alteration to the crossmember "not sure never did this" oh th gas pedal cable to the carb will need changed as well year one sells them for sb400 "you might want to double check on it" as well as the emergency brake cable intermediate and hangers "should be three of them" this is all i can think of hope it helps you alex ------------------ hmmmm the sound of wrenches turning and... slowly out from the garage emerges a luxury muscle car that is anything but... it is.. the monte carlo with a new edelbrock performer rpm power package and new 350 block stroked to 377 cid. Link to comment Share on other sites More sharing options...
chuckash Posted March 6, 2002 Share Posted March 6, 2002 The 400 sb should go right in where the 350 was. The only other thing that comes to mind is the radiator. When I purchased my 70 with an original 400 sb, it had a three row radiator. I believe that the radiator was the original. If you have a two row, it would probably work fine. Cooling on the 400 is very important, as they didn't survive overheating too well from what I have heard. The front motor mounts should be interchangeable from the two motors. Good luck. Link to comment Share on other sites More sharing options...
Guest Posted March 7, 2002 Share Posted March 7, 2002 Yes on the flywheel and balancer. externally they are the same so it will work with the 350 mounts. if that 700 is stock and not beefed up it won't live behind the torque of a 400 very long, the harder you run it the shorter it's life. the 700 is some what like a turbo 350 with a couple of clutchs removed from each pack to make room for the 4th gear. they can be reworked to handle it though. Don Link to comment Share on other sites More sharing options...
Guest Posted March 8, 2002 Share Posted March 8, 2002 I did the exact same swap 13 years ago. The 400 drops right in where the 350 was and all the cables, wires and bolts hook up in the same places. You will indeed need the 400 balancer and flexplate (flywheel in my case) but everything else is the same. You will need to drill steam holes in non-400 heads. I had to do this on the Edelbrock Performer RPM heads I bought, but the heads came with excellent instructions. ------------------ Huibert http://home.twmi.rr.com/hmees/monte_index.htm Link to comment Share on other sites More sharing options...
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