Will it work in my car???

[mojo92]

Ok I am rebuilding my engine a L98 after we got the motor out, my dad said that I could have his 400 block with 350 cast iron heads 4 bolt main. Will it work in my car if I put my intake and other accessories on it. My dad said it would as long as I use my intake and other things that go on the stock motor, he also said that a block is a block any will work as long as you put everything back the way it goes.

 

[JimBobC4]

Isn't the 400 balanced differently ? I'm not sure the harmonic balancer and flywheel or flexplate will work. Also, does the L98 have knock sensors in the block ?
If so , your 400 probably wont be tapped for those.

One last item, you may want to check coolant flow paths. Another words, I think the coolant in an L98 flows different than in a 400. If you take the heads off you will notice different coolant paths into the heads. I would speak with a competent machine shop about this. The heads bolt up,
but I think it may create hot spots in certain areas that will result in a
cracked head.

This info is from the memory of building a 400 small block many,many years ago for a 1970 Camaro so take that for whats its worth.

However, I recommend research and caution here.

 

[JAKE]

Using a 400 block in a L98 is a common swap; I ran one in my 86. The 400 block has the provision for the knock sensor, just remove the plug.

You'll need a 400 starter and a smaller diameter damper, since a 8" damper won't clear the rack and pinion.

If your 350 engine has a roller block, you'll need a retro-fit roller camshaft/lifter/pushrod setup or go with a flat tappet cam/lifters/pushrods for the 400.

There may be a couple of other plugs that need to be removed to accomodate the coolant temp sensor, temp gauge sender, oil cooler, etc. The 400 block is a 2 piece rear main seal block and your 350 block is 1 piece.

Jake

 

[JimBobC4]

" All Chevy V8 (1962-1985) engines are internally (or neutrally) balanced and flywheels/flexplates interchange between them. The exceptions to this are the 400 c.i.d. Small Block and 454 c.i.d. Big Block V8's. These each require their own special balanced flywheel. Using a neutral balanced wheel on either of these engines or using either the 400 or the 454 wheel on a neutral balanced engine will cause vibrations that could damage the engine. These external balanced flywheels or flexplates can be identified by the obvious addition of weight to the side of the flywheel facing the engine"

This is a cut and paste off a Hot Rod site for v-8 conversions.

http://www.novak-adapt.com/knowledge/chevy_standard_shift_info.htm

I think its balanced differently. It may bolt up but if its not custom balanced its gonna vibrate itself to death. Been a while since a built a Chevy, but I have built a few 327,350's and one 400. In either case if your banging gears at 5 grand I would get it balanced WITH the flywheel and balancer of your choice.

Also, check this site about the siamiezed (sp ?) cylinder block and the steam holes in it that I had mentioned before. Again it may bolt up but it causes hot spots in the heads and they crack later in life.

http://www.hotrodders.com

do a search for 400 and steam hole

I'm not saying it won't work. I'm saying do your research before you bolt it together. It will fit, but things are different that won't come to light immediately.

One last thing. The first 400 was produced in 1970. Your block may or may not have the plugs for the sensors. If its a 4 bolt main it was built prior to 1973. 2 version exist.

try this site for engine ID

http://www.nastyz28.com/sbchevy/sblock.php