BBC 396 stroker

[rocketracer380]

Any insight on this combo currently running .060 396 cc square ports mild porting 12:1 comp .714” .680” sr tunnel ram with two 660’s I m a 3400lb Camarillo has gone 10.60’s lookin to put a 4” stroke and possibly 4.185 bore any thoughts lookin for lo 10’s

[amc fan]

I would sonic test the cylinder bores before trying to take it to 4.185, Why not sell that block to someone who needs a 396 and start with a larger bore 427-454 block. Cylinder walls are not as thick on a 396 and tend to split at that bore size. I think there was one year that 396's were thick maybe 1965 IIRC.

[F-BIRD'88]

If you now want a bigger motor save the hat one and build a 454 block based motor. (496 ish)

Keep that one for a spare.

[pamotorman]

I would sonic test the cylinder bores before trying to take it to 4.185, Why not sell that block to someone who needs a 396 and start with a larger bore 427-454 block. Cylinder walls are not as thick on a 396 and tend to split at that bore size. I think there was one year that 396's were thick maybe 1965 IIRC.

the only BBC 396 block that could be bored to 4.250+ was the 65 corvette 396 block because it was cast to be a 4.250 bore block before GM higher ups said nothing over 400 cu in.

[Alan Roehrich]

No reason to even begin to consider putting a 4" crank in a 396 block. Just buy a 454 shortblock and build it.

And honestly, guys in Stock Eliminator are running 10.0 in a 3200# Camaro, with a 396 big block, a dual plane intake, a 780 Holley, and a 0.520" lift cam.

[pdq67]

I have read that if a wooden pencil wouldn't fit between the cylinders when stuck in a freeze plug hole that a 396 block would bore to 4.250"..

And I have a 496 in my car now.

As for another engine, I would hunt up a 502 block, bore it .060" over and install a 4.375" stroked crank and make a 564" engine. Say at 9.5 to 1 CR, and cam it mildly and build for grunt and then go have more fun than John Law will allow!

pdq67

[jeff swisher]

I am wondering if something in your combo is holding the car back.
Dads buddy ran a 425HP 396 with NO head work in a chevelle in super gas class and crossed the stripe at 8000-8500rpm I remember he said he changed the cam but it was .575" lift as what he ran and dual 4 intake with 2 carter AFB carbs .. it ran 4 speed and 411 gears 9.8 et was his best.
2" headers and 4" collectors 18" long.
He stuck it on a dyno and it made 625HP at the crank.

Now the little 396 wants to rev and if you stop at 7000 rpm i feel you are missing out.
Especially for rectangular heads. If the headers are right I would say try larger carbs.

I run 2 600's on a tunnel-ram for daily driving mild sbc 350 stuff (under 450HP).. tried smaller and lost power.
Tunnel-rams like large carbs, at least for me and my buddies running them .

I just feel you have some low 10 possibilities without taking major parts off of that engine.

[pdq67]

Wouldn't a pair of 2.19"/1.88" big-valved -781 or -049 Large oval heads be better than a pair of rect heads on a hopped up 396 only because of cubes?

Just make sure that your CR is what you want it to be is all.. The old -206 BBC large oval heads have combustion chambers down around 96.7 to 98 cc's and they are true closed chamber heads. The old -215's are semi-closed large oval heads at something like 112/113 cc's or so..

The -781 and -049 heads should be right at 118/119 cc's, BUT cc them so that you will know for sure!!

pdq67

[ClassicComp]

What's the whole combo soup to nuts? I run a 396, it goes 10.teens at 132.@3400lbs.

[rocketracer380]

396 bored .060 .714" .680" Sr victor tunnelram two 660 carbs hooker 2" primaries 3 1/2 flomasters 9" nos converter approx 4,500 stall 5.13's and 29" tall slicks I believe tranny was slipping in 3rd best pass 10.6 @127 all steel 69 3400 # with driver on an aborted nos pass I went lo tens @ 115 200 shot heads are mildly ported they came off a low ten sec 454

[Alan Roehrich]

Yeah, something seriously wrong, and likely not just the transmission slipping in 3rd gear. A good 396 Stock Eliminator 69 Camaro weighs around 3450# with driver in A/SA, and will go 9.95 at over 130MPH in decent air. That's with 9" slicks, a 5.14 gear, a light three speed automatic. 5500 stall 8" converter, a 780 Holley, unported heads, and a 258/268 0.520" lift flat tappet cam.

Your Camaro should go at least that quick/fast. Unless maybe you're in Denver.

[ClassicComp]

cam card info? How high do you turn it? 60ft time? Altitude you run in?

[rocketracer380]

Comp roller @.050 276 280 ls 108 4500-7500 int .714" .ex 680" 1.40's 60 ft needs higher stall I ran with 9" nos converter @ sea level raceway park atco home track

[rocketracer380]

Can't compare this engine to superstock engine my steel headed 468's usually run 9.90's 10.o's @3200/3300 these heads went
Low 10's on a 468 with the same cam shifting at 7600 I think with a looser converter and spinning it higher it would have been faster plus it was slipping bad in 3rd

[jeff swisher]

Fix the issues you know you have like slipping in 3rd.
before you change anything else.
for that duration 7500rpm seems low..
I have also seen as much as 4 tenths in a converter change.
You seem to have the cam and heads and i do not think the cubes are holding you back.

I just finished a tunnelram swap on a buddies 396" last night. Took a strip dominator off with 800cfm carb.
And installed this tall ram with 2 600 edelbrocks and it has a 230@ .030 comp cam 280H ground on a 108LSA.
Ported large chamber oval ports 2.19-1.88 valves 2" headers and 3" exhaust with Mufflers 11:1 compression and 210 psi cranking pressure on 91 octane fuel.
His first drive last night to 7/11 and back left him shaking .. he said it was "Raunchy".
Which i take to mean as a good thing said he was in second gear (TH400) coming around a corner and just touched the throttle to speed up and tires broke loose accelerated quick and shift light came on quicker than he could pull the next gear.

Said it never did that before.
We were shifting it at 7000 . I shimmed the valve springs .030" same time I did the tunnel-ram swap as the thing would float valves a little earlier than I thought it should.
No floating now.
That one is just a good daily driver work truck.
7500rpm comes on quick.
Yours has a lot of potential.