Destroked long rod 400 SBC

[ramey36]

Lat G friends:

I have a stock bore 400 block just waiting for a home. Has anyone done the long rod, short stroke engine lately? We used to build 377's all the time for oval track use.

With the advent of awesome heads and lots more rod choices I'm wondering if this would be a worthwhile engine to look into.

This would be for auto-x and open road course track days in a 3400 lb G-body.

ramey

[Bad94]

I built a 3.48 stroke x 4.125 Bore motor few years back and run it in my nova. Strong motor, pulls crazy from 3500-7000 plus. I have AFR 210 CNC heads and single plane intake with Holley EFI, all lightweight rotating assy, and very light clutch set up(26lbs with box)

If I was going to build it over I would go with more compression, and maybe bigger heads.

[Flash68]

My Camaro had a 377 in it when I got it in 2010. Ran it hard for 2 years and loved it. But it was not very well suited for autoX and more at home on a road course. It still really lacked the low and mid range torque. Once it woke up around 4500-5000 (mine had a pretty darn big cam) it was a fun thing. I had the rev limiter set at 7400 most of the time. :)

For an all around motor for both venues I would build something with more cubes and a little more stroke. If I was building something from scratch I might do what the 410 cube sprint cars run...... 3.80 stroke or right around there.

As you probably know those stock 400 blocks aren't very well thought of.

[Neil B]

I recently completed a 4.125 x 3.480 372ci motor. It made 580 on the dyno and it's going in my '69 Camaro. It's hard to beat this sound...

https://www.youtube.com/watch?v=D2O0ROhmUhU

https://www.youtube.com/watch?v=nVaFa7zLiSU

[Vince@Meanstreets]

If you can increase the cooling to stand up to sustained race use its a great block. 400's were hard to find so we started to use 392's alot. 3.832 stroke 4.XX X bore 5.7 rods made a great combo.

then the LS came out

[ramey36]

Thanks guys. I appreciate the responses.

I'll keep researching and learning.

LS of course is awesome but I have one car which I'll probably keep as SBC.

Thanks!

-- Ramey

[XLexusTech]

Dart shp block or a little m if you are committed to gen 1 SBC

[GregWeld]

My 4000 pound 56 Nomad ran a 408 Dart Little M based SBC... with peanut Dart 180 CC heads. Made 550 ft lbs of torque at 4600 RPM and 524 HP at 5600 RPMs (all out of air with the little heads). The thing rattled windows and set off alarms. Pulled like a freight train with a 2800 stall convertor.

Having said that - there's no way I'd invest fresh money into an old skool SBC build these days. The LS platform is just so much better in so many ways. You can get the torque and HP with such minor mods - or just buy the 525 HP LS3 and be leak free... lighter weight on the front end... and be reliable with no stress and less cost. You're under 10K with the controller and DBW throttle... I think Pace sells the motor for under 8K and the controller package is around 1200 bucks. You can't build a bad ass 400 cubic incher for that if you have to buy heads and crank and rods etc.