Thread: biggest stroke

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im plannin on building a small block and was wondering what the biggest stroke i can use in a 350 block is. ive read about a 3.875 stroke just wondering if the block can be clearanced for anything bigger. i need torque!!!

What is your desired result? What is your application? When you say “I need torque!!” are you pulling a boat? Stumps? Or do you just want to tear up things? More info will get you a better answer.

One way to increase torque is to lengthen the crankshaft stroke (as stated by Denny) and the rod length to the maximum possible. Try and get your compression ratio to 9.5:1 - 9.75:1 with iron heads (use Vortecs). Use a hydraulic roller camshaft specifically ground for high torque and use roller rockers.

Bear in mind that your crankshaft weight plays here too. A forged 350 crank (stock) weighs 50-53 pounds, depending on if the leading and trailing edges have been rounded. 3.750 is going to be 54-55 pounds, 3.875 typically come in at 54 pounds.

If you’re running an LS1 – you can go all the way to 4.250 stroke with a crank that weighs 54 pounds.

we have been using cranks that weigh 41 lbs in sbc using Dart 4.125 SHP blocks---

a 3.875 crank i a stock sbc chevy could be tricky if there any core shift would have to cut abit out just to get a 3.750 in one . there been more then one guy thats hit water cutting to clear the stroke .as well as the rods may need to be nip if you use a thru bolt rod . if you use a H beam stroker rod help s clear the bass circle of the cam .a small base circle helps as well. if you did the 4.875 to 4.000you may want to look at a rod that used a small journal or honda on the 4.875 in a stock block i would look at a better block .for low rpm max TQ i would not worry much about 10 to 9 pounds on the crank weight. spend your money were you will see the best bang for the buck

If you use a tall deck Dart block, you can build a 454 SBC (4.185" X 4.125").

yep you can.. so why play around i can get in a bbc dart block or other makes 4.600 X4.375 crank in a 9.800 =581 or a 4.600x4.750 in a 10.200 =632 EZ or a low buck 512 cid in a gm 9.800 stock block or 496 OR a 11.500 block with a 4.610X 5.500 =735 so...do you want to pull stumps

I notice mousepower has gone silent on us.... hmmm

Originally Posted by glennsexton

I notice mousepower has gone silent on us.... hmmm

what did you do to himyou sure like to stir the pot
glenn

Yeah Glenn, what's up with that?

We have built a 478 out of after market tall deck. We have built a 454 with stock block and it ran great with no problem.. You can get by with 4" stroke in a 350 but I wouldn't mess with it. I rather go with 400 block and put in a 4" stroke with .030 over bore will have 434 Cid.

sorry it takes me so long to reply but thanks for the pointers basically i dont wana go as big as i possibly can but was figuring out my options. i think that ill prolly stick with the 350 block cuz theyre a dime a dozen plus when people ask what ive got under the hood all theyre gonna get is "its a built 350." to thro them off a bit. but if someone out there (hint hint) has a good 400 block theyre willin to get rid of then id go with that.