N2OBaby

I bought Car Craft's most recent issue for a story about a Blown 468 Chevy2 read it and laid it aside.

It was only after brucers's post about his 402 BBC did I pick the mag back up.

In Car Craft they built a 461 Stroker from a 396 (+.061 overbore which is the same as a +.030 over 400 SBC, 6.385 inch rods, and a 4.25 inch BBC crank) then complained about the heads & intake which were stock.

They didn't dyno this engine but suggested output was 425 HP & 500 LB FT of TQ.

Brucer had a quote that 402 BBC rev like a SBC but make more power.

Why not enlarge the 396-402 to 434?

(4.155 400 11.75-12.5:1 forged pistons, 6.385 inch forged rods, a 4 inch forged crank, an Edelbrock Street Tunnel Ram, ported Aluminum Oval Port heads, and a solid roller cam with an ephasis on Mid & Top end power but has a lobe seperation of around 112-114 degrees, twin E-85 750 Dominator carbs) Would this be a engine that could rev like a 383 SBC but crank out 520-670 HP/ 520-600 LBFt of TQ and not be peaky?

What do Ya'll think?

ZONES89RS

iTrader: (25)

Cube for cube, the SBC should do better ith aftermarket parts due to less rotating mass i would think, not to mention stroking a 396 up makes the stroke larger than the bore, and that is not something you usually want for racing.

pancherj

On smaller BBC's, the only advantage I see over a SBC is valve area per cubic inch. However, I would be wanting a larger bore 427 to make good use of that large intake valve!

brandoz28

iTrader: (3)

it'd be sweet if you were packin it full of boost or a ton of nitrous, the bbc strength would be nice

brucer

i believe a 396 or 402 stroked out to a 427 or a 434 bb would be a damn nice engine with some nice oval port heads on it, just make sure you use undercut valves or have your head builder use a smaller stem valve when he builds the head..... the thing is you can find oval port bb heads pretty cheap, and you dont have to spend a ton on them getting them built.. just get the better oval port heads.

the bore and stroke on the 427/434 stroker kits for the 396/402 blocks are 4.125/4.155 bore and 4.0 stroke.. i would use the 4.00 stroke crank, and at that point would go to the 4.155 bore and the 2.187/1.875 undercut valves or 11/32 stems..

the smaller the bore the worse the shrouding would be, so the 396 stroked out to a 434 with a bore of 4.155 would be pretty good i think..

one reason i like bigblocks is that the rpms dont settle as fast as small blocks, i like the enertia on a bigblock... i believe when the trans shifts the engine doesnt loose as much rpms which makes smoother power... i think thats why big blocks usually have a nice flat torque curve..

i think a 396/402 stroked to the 427/434 using a 4.125/4.155 bore and 4.0 stroke would be badass no doubt about it.

i know if i had a 396 or 402bb laying around and pondering of building a smallblock 427 or 434 i wouldnt think twice, the bigblock would be built before a smallblock for sure.. for that matter, you'll have to pay alot to build a big smallblock because you'll need aftermarket block and heads.. the big block you just need a stroker kit... the thing is the big block will run better on pump gas because of the combustion chamber volume..

brucer

adding this,

i got an rv cam basicly, just alot of lift on it for an rv/towing cam but the same basic standard applies.. with my 3800rpm converter i'm pretty much at my peak torque, i can run up to 6200 rpm before it flattens out on the topend.. i could use more cam for sure, a .600 or .625 lift roller would be nice.. but the cam i have drives on the street very nice, i'm running 11:1 compression with cast iron heads and i bet i could run 89 gas in it, i dont but i almost bet i could..

thats another thing, you can run a little more compression in a big block because of combustion chamber volume, and 200hp shot of nitrous isnt actually alot on a bigblock....

a 434bb 4.0 stroke 4.155 bore would be an animal with about 10lbs of boost on it..

you can look up the engine masters challenge 427 stroker... the guy built a dyno 396 bored to 427 with a 4.285 bore and 3.75 stroke and like 2.30/1.86 exhaust valve .820/.780 lift roller.. it put out 700hp & 600ftlb of torque 10.5:1 compression on pump gas.

pretty good article especially angle milling the heads and intake at the bottom of the page... old school mod and actually how the 18* heads come about.

xx_ED_xx

iTrader: (17)

An overbored 427 makes a good rpm motor. not an over stroked small bore motor