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Author Topic:   377 half fill
regal 22
Dirt Full Roller

Total posts: 28
posted May 12, 2005 05:57 PM  
Has anyone ever had any luck with this kind of motor? The reason i am asking is, recently a friend hooked me up with this combination: a 400 small block bored 60 over forged 350 crank with bearing spacers,block fill halfway up to the freeze plugs ( for strength he said),keith black claimer pistons,reconditioned gm rods, 550 lift comp cam,hyd lifters,202 bowtie heads and high rise gm cast iron intake. I had the car out in the heat race the motor was extremely strong,but lost power steer belt so I could not push it to potential. On the 2nd lap of the feature the motor let loose. #4 piston lterally blew apart into many tiny pieces. The motor guy said he can put a sleeve in and order a couple of pistons and have it ready to race soon, my question is do I want to redo this motor or will it allways be a problem motor. any helps and or tips would be greatly appreciated, thanks in advance

Dirt Freak

Total posts: 369
posted May 12, 2005 07:05 PM  
i have heard of lots of over heating problems with 400's then you have hard block in the water jackets (which works for drag motors for strength but they shut them down in a very short time span not after 10-20 laps) i would not recommend this block. change blocks but as far as going 60 over on a 400 it is not recommended because the cylinder walls are to thin unless your using a dart block or a bowtie block

your just begging for trouble with that

drive hard or drive home

Dirt Maniac

Total posts: 136
posted May 12, 2005 10:08 PM  
Back when this combination was first popular(late 70s)Everybody was blowing them up(usually wasn't enough left to tell what caused it)For some reason(something to do with geometry)they tend to jack the wrist pins out.We tried everything to prevent it (spirolocks,double spirolocks,nylon pin buttons etc.)finally went to pressed pins and never had any more trouble.The half filled block will work but you must drill steam holes in your heads to match the block,at least that has been my experience.

Dirt Forum Racer

Total posts: 94
posted May 13, 2005 06:30 AM  
the combo is a descent one,the destroked motors scream really well,and grab rpms easy,but the 400 blocks are literally not that either get a good one that last,or one that doesnt last and blows,its always a hit or miss with them.i know alot of poeple that love 400 and i know alot of poeple who will not touch them..ive seen way too many problems with the 400,the geometry in them isnt right and the castings are very poor.a very well known engine builder that uses this site often will tell you if it is over 550hp then throw it away..

Dirt Forum Champ
Total posts: 796
posted May 13, 2005 06:54 AM  
What Jpotter94 said, and at .060 over a 400 blk is a time bomb. Plus you will never keep it cool on race gas.

Get another block and just bore it over to the minimum you can get away with. .030 max.

Dirt Forum Champ
Total posts: 501
posted May 13, 2005 07:50 AM  
I was told that when you put a sleeve in, that it distorts the bore(s) next to it, so they have to be bored to the next oversize. Since you're already at .060, I'd agree with everyone else, find another virgin 400 block...

Dirt Forum Champ
Total posts: 2007
posted May 13, 2005 08:04 AM  
If you are going to push any serious HP out of a 400 block and want it to last any good length of time I would advise looking at a Dart, or Bowtie block. Juse like posted above, with stock 400 blocks lots of times you either get a good one or you get a bad one, but either way much more than 550HP and your pushing it...

regal 22
Dirt Full Roller

Total posts: 28
posted May 13, 2005 03:00 PM  
I thank all of you a lot, basically the concensus is, a good powerplant but with a better block, is this combination really capable of over 400 hp, not being sarcastic I just don't know!

Dirt Forum Racer

Total posts: 94
posted May 13, 2005 04:06 PM  
over 400hp is easy out of a 400 block.the 377 combo in a dart block is capable of 600hp and even more depending on what all heads and cam combo's you use.there are aluminum headed 377 cranking out 650hp on alky

Dirt Roller

Total posts: 15
posted May 13, 2005 08:36 PM  
I have ran a 377 for about 31/2 seasons.It is a plain claimer.Speedpro pistons stock crank stock 5.7 rods. Normally turn any where from 6500 to 7000.Engine builder said that it would never last turning over 5500.It has well over 100 races with bearings replaced twice.

Dirt Forum Racer

Total posts: 94
posted May 13, 2005 09:17 PM  
waynedogg--you must have got a good one that is all there is too it,steve at hendrens will tell you the same,like we said earlier in the poost they are a hit or miss item,they are either good,or they are junk

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