Small block w/ 3.79 crank
- Thread starter tvt59
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AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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IDK, should fly if the pistons stay straight, lol.
OldmanRick
Well-Known Member
Probably not worth the expense for anything other then a ''class specific'' car. With those rods, most are built with big heads, big comp, big roller, and turn a lot of rpm. Not that it wouldn't be fun with a 5spd and some big gears. 
I've always wanted to build one. W7 headed, 14 to 1 or more and a solid roller. Was just wondering if anyone had experience with that combo.Probably not worth the expense for anything other then a ''class specific'' car. With those rods, most are built with big heads, big comp, big roller, and turn a lot of rpm. Not that it wouldn't be fun with a 5spd and some big gears.
I knew a few guys. That’s why I didn’t reply. I don’t personally know. The additional info of a W7 head puts me to knowing one person. It’s on a 340, not a stroked mill. He is assembling it now.
The 6.50 rods I’ve never heard of anyone doing.
The people I knew running a 3.79 stroke crank normally ran the W2 into the low 10’s and 9’s. They were bracket racers in the 10.0 index. I don’t think they were at 14-1.
The 6.50 rods I’ve never heard of anyone doing.
The people I knew running a 3.79 stroke crank normally ran the W2 into the low 10’s and 9’s. They were bracket racers in the 10.0 index. I don’t think they were at 14-1.
Should work fine, what are you looking to get out of it vs 340/360/408+ torque and rpm wise it will be between 360 & 408. It probably won't nose over after peak hp as much as a similar 408.
ValiantS
Well-Known Member
It will work, so will the same crank a shorter rod and taller piston. you'll never notice the difference. Unless the piston design is so compromised by excessive rod length. You have a PM
800 hp @ 8000 rpms is 525 lbs-ft @ 8000 rpms, torque at peak hp is generally around 85-95% of peak torque, an engine this level probably over 90% say 92% so peak torque be about 570 lbs-ft. So for a 387 cid = 1.47 torque per cid up there but not out of the realm of possibility.
EdsWelding
Well-Known Member
We used big block chevy forgings in our SBM and the rod length was 6.442, reground rod journal on crank to small chevy of coarse. We did not have that much stroke, we patterned ours off of a couple guys from Cleveland that ran a Duster in the very early days of Pro Gas. There car was black with the name "Marfezio&Furmancheck" on the side. Sam Gellner built there motor.
That's a lot of power out of a stock block.
I have two R3 tall deck Siamese blocks one is 59 deg the other is 48 deg.
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Molinar makes a 6.50" long SBC rod.
All the better, sounds like gonna be a killer combo
What are you doing for pistons?
Race Tec and Diamond both said they could make the pistons in about 6 to 8 weeks. With pretty much any ring combo that we want.
@intimidator, what combo do you run?
mopardude318
Well-Known Member
I have a Molnar 3.79 crank with 2.1 journals, and Molnar 6.2” long power adder rods I’m having built with a 671. Custom pistons of course, but still collecting parts little by little.
TT5.9mag
Two atmospheres are better than one
You’re going to need every bit of that w7 head. And it’s gonna be awesome.
They ran those heads in some NASCAR classes and made about 850 hp. I can do what I want to do with 800 hp. I hope it's works out.
TT5.9mag
Two atmospheres are better than one
Didn’t the NASCAR truck series run that head?
Goal for my next build is to run a 3.79 crank.
I think so
lead69
hopeless car junkie
That is going to be awesome, my dyno partner Tim has a couple 3.79 cranks and at some point he is going to build one. We are always discussing builds to dyno test with and really wanted to find a way to do one with a 3.79 crank. We think the hp would peak at a higher rpm than a 4" and make more power as a result. I would love to throw one in my stick car, I may have to make it happen at some point.
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