Posted By: Overdrive440
Stock stroke 400 - 02/15/11 12:49 AM
What pistons are currently available that would work on a stock stroke 400? I read about hemi rods and 451 pistons, but not sure what pistons would work for that combination.
A little background: I was in the process of rebuilding my truck's 400 and got a 383 crank ground and new bearings for it, but my project stalled. This was a few years before stroker kits became available. I'd like to use the crank I have, so I'm looking for new rods and pistons to finish the shortblock (flat top, zero deck is the goal). I'm likely going to be using Edelbrock RPM top end or better (Indy EZ top end kit).
This is going back in my '78 W200. I'd like to try out some of the local truck pulls with it again.
Posted By: 8secDart
Re: Stock stroke 400 - 02/15/11 01:43 AM
ONE WORD(custom)!!!!!!!!!!!!!!!!!!!
That is why no one does stock stoke 400s.
Years ago KB had a piston for this combo but I have not seen any in about 10 years.
I used a low compression 440 replacement piston .060 over for a mild build once. The piston ended up .008 in the hole. Worked well for a mild street car on pump gas. I don't remember what piston exactly.
Posted By: cjs69mope
Re: Stock stroke 400 - 02/15/11 01:58 AM
Here you go KB pistons not hard to find .
web page
Posted By: Overdrive440
Re: Stock stroke 400 - 02/15/11 03:04 AM
Ah! at stock deck height these are 0.024" down the bore. Guess I can have my deck shaved while its all apart.
I also see Ross lists custom forged pistons for NHRA stock class: 400 72-78 78691 FLAT TOP
Those might work too...
Posted By: 383man
Re: Stock stroke 400 - 02/15/11 05:38 AM
We have the KB pistons in my sons .030 over 400. With Eddy heads milled it has 10.6 comp and runs fine on pump gas. He has a stock stroke 383 crank and uses the MP .557 cam. With a 9.5 Dynamic converter and 3.91's he has run 11.40's in good air at 3550 lbs. Ron
Posted By: RTSrunner
Re: Stock stroke 400 - 02/15/11 05:54 AM
There is a set of KB-240 flat top pistons for sale by a member here in the Big Block parts section.They are for a stock stroke and stock rod length 400.Check the KB site,may work for you.
RT
Posted By: Overdrive440
Re: Stock stroke 400 - 02/15/11 09:08 PM
I'll have to price it out... or just go with some KB240's.
Its looking more and more that it might be worth the few extra hundred dollars to get a stroker kit and add a bit of extra torque if the KB's don't pan out.
Posted By: AndyF
Re: Stock stroke 400 - 02/15/11 09:49 PM
I've used Hemi length rods with 451 pistons before. The math comes out close enough to give you zero deck. Not sure the extra effort was worth it though, these days I'd probably just buy a 3.75 crank and build an actual 451.
Posted By: jyrki
Re: Stock stroke 400 - 02/16/11 07:59 AM
The 440 low compression pistons with stock rods should work. We had one with TRW L2266F's and they were slightly positive deck. Just contoured the piston tops slightly, cut valve reliefs and they were good for slightly over 10:1 CR with factory open chamber heads. With big valves and a comp cams 306R cam it was a screamer, turned well beyond 7000 rpm and run 10.6/128 mph in a light 2800 lbs '73 Valiant.
Many ultra low buck 400's have been "warmed up" with 440 pistons. I'm told the old .484 purple cam cleared pistons ok with no pockets and std. valve sizes.
but as always measure
Posted By: AndyF
Re: Stock stroke 400 - 02/18/11 05:17 PM
Yeah, that was too bad that Manley stopped making that rod. Those were really nice rods and the price on them was pretty good too. I bought several sets of those rods there at the end but I've sold them all over the years.
I happen to have that 400 motor back in my possession these days. The guy I built it for ran into some financial problems and I bought all of his Mopar stuff. I don't have a use for it at the moment but I'm sure something will come along. It was a high winding 400 with the stock stroke, roller cam, long rods, and high compression.
Ron