I want to upgrade the rods, and pistons, in the 383 in my Dad's Super Bee, It currently has stock rods, and old KB pistons. Want to switch to a set of Molnar rods, and forged pistons. Since it needs a custom piston anyways (currently .040 over) I was wondering if anyone runs this combo? I know it's been done many times with a stroker crank. This is for a street car only.

Thanks.

I just got finished putting together a combo like this. I am running a .030 over 383 with the K1 6.760" 440 rods and using a factory forged 383 crank. I am using a custom Wiseco +18cc dome piston because I wanted higher compression and have Trick Flow heads, but I know Diamond has some part numbers for a 3.375" stroke and the 440 rod although from what I recall they may only offer .030" and .060 over" as shelf options.

With the dome, what does your compression ratio come out to be? The engine has Edelbrock Performer heads on it. Id like to get the compression to around 10.5:1.

With the 78cc chamber of the TF head, Cometic .045 head gasket, and -.003 deck clearance it calculated out to somewhere between 12.3 and 12.4 : 1. I had the pistons lightened and that shaved off about 40 grams and I want to say they ended up weighing around 580 grams when finished. I think the Performer head may have a slightly smaller (75cc?) chamber? To get to 10.5 : 1 you will probably still need a small dome. You may be able to achieve that CR by shaving the heads and running a thinner head gasket although just having a custom piston made may be simpler and less expensive. To be honest these pistons I had made were fully custom down to the shape of the dome based on the TF head and only cost a few hundred dollars more than the 383 w/440 rod pistons Diamond lists part numbers for. The worst part for me was trying to find a set of Molnar or K1 rods with the supply chain issues but after posting a want ad here I was lucky enough to have a member here contact me and he was nice enough to sell me a set he wasn't using.

I'm building this combination for a medium-weight street/drag car: 6.76 PEP rods (this gives the combo a 2:1 rod ratio), Diamond 51907 shelf pistons (flat top pistons with valve reliefs), .000" deck, Cometic C5460-036 gaskets, (or the .020" Chrysler gaskets with -.015" deck), ported 915 heads cut to 65 ccs which comes out to approx 11.4:1 static. You can play with the Wallace compression ratio calculator (I have for years) or do the long math, but their SCR calculator is pretty close, just add your specs and voila, a ballpark estimation! http://www.wallaceracing.com/cr_test2.php

If he sold one old junk tractor, he could use the $$ to put in a stroker crank.

Very true, but then the snowball effect starts. The car still has it's numbers matching block, and transmission. While the car will never be for sale, I still don't want to take a chance wrecking the original block. Then you need to buy a new cam, upgrade the fuel system, etc.... It's a street car that gets driven a few times a year. It has more then enough power to destroy tires as it is.

How about finding a decent 440 crank and have the mains turned down to B size and have the crank offset stroke to BB Chevy size and increase the stroke to 3.91 and use some after market BB Chevy H or I beam rods 6.8 or 6.7 long to really wake that Super Bee up
I do that to some of my milder 400 blocks I build for customers who want to do a low deck build a little cheaper than going with a new stroker crank, rods and pistons

One of 'Those guys' hmmmmmm.

What makes this funny is Joel telling somebody he needs to get rid of something. Lol

Diamond will make them in the oversize needed , shouldn't cost much more than what they charge currently for the piston ... which isn't as cheap as it used to be ...

I have that exact build here , 6.70 rods and 1.32 CH , though his oversize at .040 is going to require a semi custom as that is not a common oversize.

My pure stock 383 build the Dan built for me has the Diamond shelf stock 383 piston in it at .040 with a smaller 3 cc piston notch. At zero deck with a set of 80cc 906's it's close to 11.0.

FYI, Manley ran a small run of 383 I-beam rods a couple of years back for Stock/SS 383 racers. I bought a set for a SS 383 I'm building. Jim Hale was supposed to buy all of them but wimped out. They are fairly light at 810 grams and I-beam design like their Pro I-beam rods. Not cheap at nearly $1500. The long rods are a better choice for non-NHRA legal engines.

I’d bore the main bores out to 440 size, more crank choices out there

I do have that hoarding thing in common with Jeffs dad. But I think the theory was supposed to be hoard stuff now, then live off the proceeds when you're retired. Except for the stuff you really like. Which is almost every thing...

Why weaken the main bore in the 400 blocks?

That's a bad move in a 383 block , the main webbing is already paper thin.

I didn't know that , I had Dan Costello prep a set of stock rods for my 383 Pure Stock build , at the time the only other choice were Eagles. I'll have to keep my eye out for some ...

'source might have had something but I think they were made of 5140 ... only good for lawnmower engines ...

I haven't built a 383/400 in a long time but if it were me and a non-class restricted combo, I'd offset grind the rods to 2.200 and a 3.51" stroke and use an off the shelf mopar width BBC 6.535 or 6.700 rod and run a lighter .990 pin piston as well. but even keeping the stroke the same the 2.200/.990 is a huge plus especially since any 383 4.25 based bore is starting off as a 427 BBC piston blank anyway.

Of course long rod ratios keep the angularity down and the 'dwell' "up", which was great for holding on the compression when all we had were relatively poor flowing OEM heads.

I had once planned on a 422" long rod B motor combined with something like a TF 240 head to make for a pretty sweet little high-revving medium-size motor that would be easy on a factory block and should last forever compared to a short rod stroker. and with enough gear and converter you could concievably make about the same power and ET

And if you wanted to get really crazy you could de-stroke the crank to 3.23" or so and build a 400 based 389" with TF 270's and a 7.1" rod (~1.26" compression height piston) and see how high we could really rev a B wedge.

But if I was using an LY or similar oem rod with a 1.09 pressed pin, i would definitely do the old Landy trick and whack 1/2" off the pin and save about 50 grams per slug. you're gonna have to re-balance anyway so why not take out weight instead of add it back?

Something like that never even crossed my mind ... now I'm going to have to take the 383 that Dan did for me apart ...