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400 block motor mount compatability

Stroker68

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Hello. Newbie to the forum. Seeking knowledge. Looking to build a 400 low deck for my 68 runner and was wondering if there are motor mount location differences over the years. I currently have a 383 based engine, and am wondering if the 400 will drop right in, or if there better years than others for swaps. I believe there may be differences between pre ad post 73 engines, but not sure. I'm looking a at good running 76 400, but want to make sure I'll be alright with the motor mount deal. Thanks in advance.
 
Thanks very much for the help. So...no motor mount location issues with the 76 block and the 68 k member. Awesome. Just needed to verify. Yes. A stroker again. 440 crank in my old 383. Home job 906 heads. Worn Isky 1012B from the 70s. Farm motor at best. Suprised quite a few people. Not much money so I can't waist any. Are all 400s the same?
 
Thanks very much for the help. So...no motor mount location issues with the 76 block and the 68 k member. Awesome. Just needed to verify. Yes. A stroker again. 440 crank in my old 383. Home job 906 heads. Worn Isky 1012B from the 70s. Farm motor at best. Suprised quite a few people. Not much money so I can't waist any. Are all 400s the same?

Yes and no.... The super desirable block is the early "cold weather block" it has super thick main webbing but there are plenty of 75-78 400 blocks making 600+ HP & it's pretty rare for one to fail...
Good info with pictures at the link below
https://www.440source.com/blockinfo.htm
 
It'll drop right in.... Only reason to look at a 400 is if your planning to build a stroker...
Thanks wild R/T. Are all 400 blocks the same in regard to motor mount geometry? Are any years better for strokers? I've got another 440 crank that's been rolling around on the floor of my shop. Figured I'd try something over the winter. Thanks again.
 
Yes and no.... The super desirable block is the early "cold weather block" it has super thick main webbing but there are plenty of 75-78 400 blocks making 600+ HP & it's pretty rare for one to fail...
Good info with pictures at the link below
https://www.440source.com/blockinfo.htm
Oops. Getting the hang of this forum stuff. You answered my question before I asked another. Much appreciated. Thanks for the link. Stroker in a kit? Sweet!
 
Some of the early blocks will go in A bodies with their original mounts that utilize the two lower bosses on the front of the block. You won't see those bosses on any later 400 or 440 blocks. I think Schumacher's site points this out; http://engine-swaps.com/Pages/InstructionPages/A-OriginalBRB.html The link is just for informational purposes, you wont have this issue unless you try to put your 400 in a smaller car like a Dart or Barracuda with original style mounts. Your 400 should fit relatively easily in any B or C body car without exception.
 
Stroker68, I built 2 400's w/440 cranks in the'80's. First used low deck rods & big dome pistons(12.3 actual), several cams,mushroom & couple rollers. Second motor used LY rods, flat pistons(again 12.3 CR) for B-1's(never got to them), both with shot peened rods, good bolts, heavily ported 906 or 915 heads(by me). As said by others, the motor mounts are the same. I didn't have the thick web blocks, my '72 was not, nor the 74. I did check sonic check a number of 400 blocks, they all seemed fairly close. The issue I had was RPM. I ran WAY too much, 7200 sometimes 7400. The cut down 440 steel crank only lasts so long, 200-250 runs. The motor with low deck rods seemed to spin up quicker. TODAY you can buy a much better crank/rod/piston combination for FAR less $$. Long stoke 400's are good.
 
About the quality of 440 Source parts... There are an awful lot of big inch Mopar's running their parts There have been a few failures and lots of finger pointing but honestly there have been failures with every manufacturers components.. Whether thats a component failure or something missed by the builder...

If you aren't comfortable with 440 Source there are plenty of shops that sell kits, Hughes, Mancini, Ray Barton, Indy... What ever you want if you have the $$$$ And honestly it's not much $$$

Read whats our there & make your choices, personally I have a 440 Source 505, It's not running but the machine shop was very pleased, I spent extra having every component checked & measured because I tend toward the extreme detail oriented side... My crank was put in the crank grinding machine just so it could be measured.. Throws are indexed at 90 degrees, the stroke is consistent at 4.25, the rod & main journal sizes were measured first by me then by the machine shop & are perfect... the rods width, length, weight are right, big end & small end bore sizes... All
 
Some of the early blocks will go in A bodies with their original mounts that utilize the two lower bosses on the front of the block. You won't see those bosses on any later 400 or 440 blocks. I think Schumacher's site points this out; http://engine-swaps.com/Pages/InstructionPages/A-OriginalBRB.html The link is just for informational purposes, you wont have this issue unless you try to put your 400 in a smaller car like a Dart or Barracuda with original style mounts. Your 400 should fit relatively easily in any B or C body car without exception.
Thanks lefty. You fellas are great. I'm knew to this sort of thing so I'll be fumbling around for a while.
 
Stroker68, I built 2 400's w/440 cranks in the'80's. First used low deck rods & big dome pistons(12.3 actual), several cams,mushroom & couple rollers. Second motor used LY rods, flat pistons(again 12.3 CR) for B-1's(never got to them), both with shot peened rods, good bolts, heavily ported 906 or 915 heads(by me). As said by others, the motor mounts are the same. I didn't have the thick web blocks, my '72 was not, nor the 74. I did check sonic check a number of 400 blocks, they all seemed fairly close. The issue I had was RPM. I ran WAY too much, 7200 sometimes 7400. The cut down 440 steel crank only lasts so long, 200-250 runs. The motor with low deck rods seemed to spin up quicker. TODAY you can buy a much better crank/rod/piston combination for FAR less $$. Long stoke 400's are good.
66. Thanks for the input. Yeah. The 440 crankmseems to twist up pretty quick. I'm a big fan. My 383 has been holding together for a while. Even with all the duck tape and zip ties.
 
It'll drop right in.... Only reason to look at a 400 is if your planning to build a stroker...
It's not too hard to make a stock stroke 383 run pretty good and the same goes for a 400. Yes, the 400 was considered a smog motor with it's low compression but who these days is still running a stock 400? I know there are some out there but not many. 400's used to be cheap just because of that and most of them have cast cranks but Mom's cast cranks are much better than the GM cast cranks and don't fail like the GM stuff. A 383 forged crank will bolt into a 400 but yeah, needs to be rebalanced. I'll take a big bore short stroke engine with mayo any day! :D Too many think a 400 is worthless unless you stroke it.....and that's not true.

Stroker68, I built 2 400's w/440 cranks in the'80's. First used low deck rods & big dome pistons(12.3 actual), several cams,mushroom & couple rollers. Second motor used LY rods, flat pistons(again 12.3 CR) for B-1's(never got to them), both with shot peened rods, good bolts, heavily ported 906 or 915 heads(by me). As said by others, the motor mounts are the same. I didn't have the thick web blocks, my '72 was not, nor the 74. I did check sonic check a number of 400 blocks, they all seemed fairly close. The issue I had was RPM. I ran WAY too much, 7200 sometimes 7400. The cut down 440 steel crank only lasts so long, 200-250 runs. The motor with low deck rods seemed to spin up quicker. TODAY you can buy a much better crank/rod/piston combination for FAR less $$. Long stoke 400's are good.
I did something similar only with a stock stroke 440 and turning 7300. After 300+ runs, I tore the engine down at the end of the year (after breaking a main valve spring...luckily, light carnage) and saw evidence of cap walk and also found a loose balancer which was stock lol. Just didn't have access to the good stuff back then or failed to know about it. 660 lift roller cam and max ported 906 heads etc etc....
 
About the quality of 440 Source parts... There are an awful lot of big inch Mopar's running their parts There have been a few failures and lots of finger pointing but honestly there have been failures with every manufacturers components.. Whether thats a component failure or something missed by the builder...

If you aren't comfortable with 440 Source there are plenty of shops that sell kits, Hughes, Mancini, Ray Barton, Indy... What ever you want if you have the $$$$ And honestly it's not much $$$

Read whats our there & make your choices, personally I have a 440 Source 505, It's not running but the machine shop was very pleased, I spent extra having every component checked & measured because I tend toward the extreme detail oriented side... My crank was put in the crank grinding machine just so it could be measured.. Throws are indexed at 90 degrees, the stroke is consistent at 4.25, the rod & main journal sizes were measured first by me then by the machine shop & are perfect... the rods width, length, weight are right, big end & small end bore sizes... All
Thanks Wild. I like the idea of the 470. Should be enough room for a half inch pickup. 4.25 stroke might get a little tight and require an external oil system. Good info on the true of the cranks. I've got a lot reading to do.
 
It's not too hard to make a stock stroke 383 run pretty good and the same goes for a 400. Yes, the 400 was considered a smog motor with it's low compression but who these days is still running a stock 400? I know there are some out there but not many. 400's used to be cheap just because of that and most of them have cast cranks but Mom's cast cranks are much better than the GM cast cranks and don't fail like the GM stuff. A 383 forged crank will bolt into a 400 but yeah, needs to be rebalanced. I'll take a big bore short stroke engine with mayo any day! :D Too many think a 400 is worthless unless you stroke it.....and that's not true.
I stood back a couple feet and tossed a 440 crank in my clapped out 383. Then tightened it down with some bolts I found on the floor of the of my shop. I did get most of the dirt off though. Been running hard for over 10 years. Only Mopar.
 
I stood back a couple feet and tossed a 440 crank in my clapped out 383. Then tightened it down with some bolts I found on the floor of the of my shop. I did get most of the dirt off though. Been running hard for over 10 years. Only Mopar.
Did something similar with a friend and his 72 Demon....ended up running 13.51 @ 102 with a very bad combination and a stock stall lol
 
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