Guest tony78_280z Posted December 7, 2004 Share Posted December 7, 2004 What is the difference between a 400 and 350. Besides displacement of course. Will 350 Tranny bolt up to a 400? What about other accessories suchas headers distributor etc. Quote Link to comment Share on other sites More sharing options...
waynekarnes Posted December 7, 2004 Share Posted December 7, 2004 if it's a 400 small block, on the outside, everything that fits a 350 of the same year will bolt on. be adviced that the 400 is externally balanced. if i remember correctly, you need to retain the original flywheel or flex plate, as well as the harmonic balancer on the front of the crankshaft. the cylinders are siamesed, meaning there is no water jackets between the cylinders, be carefull as to the head gaskets you use, again from memory, the 400 has steam holes in the block, that match to the heads, and the gasket must have those holes. also ( though for 99% of engines on the road, 4 bolt mains are not needed ), i believe that all the 400's are 2 bolt mains, though you can machine em for 4 bolts. the 400 tended to run a bit hotter than the 350. i don't remember if they were prone to head gasket failures or not. i do remember that the 400 was shunned by the hot rodders, though hot rod magazine did a write up and a monster 400 small block engine project, i want to say around 1976. but, your original question, will 99% of the engine accessories from a 350 bolt to the 400 ??? 99% of em will bolt right on. good luck, wayne Quote Link to comment Share on other sites More sharing options...
deMideon Posted December 7, 2004 Share Posted December 7, 2004 I used a 400 in my build... I had the machine shop internally balance the engine so that I could use the flywheel etc that I wanted. The only different things about the 400 is the steam holes (same heads as the 350 just needs the holes drilled), and the size of the mains. Since I was building a 377 I got a new crank from Scat so I had the mains of the 400 with the correct stroke. If you have a 400 available I'd use it... more CI more power!! Quote Link to comment Share on other sites More sharing options...
Guest 77vegasz Posted December 7, 2004 Share Posted December 7, 2004 The 400 has larger crank and rod journals than the 350, and used shorter connecting rods. The crank, rods and of course pistons are not interchangable, although you can work with them in various combos to create a 377 using the 400 block, or a 383 using a 350 block. The 400 heads have steam holes. Any small block head will work as long as the steam holes are drilled in. Most all exterior accessories will bolt right on. 400 block are getting harder to find, except for aftermarket mfgs. which cost some $$. Keep that in mind as in the future, if you want to go with a 350, allot of the internal will not be reusable. Jon Quote Link to comment Share on other sites More sharing options...
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