Took my Home rebuilt 402" BBC and ran it on a local Dyno today. Better than I was hoping for.

Here is the combo:
Blown 408 BBC 93 Octane 8.0:1 Comp ratio 32 Total Degrees timing

402" bored .030 over 2 bolt main, studded
Stock Forged Crank cut .020 and polished and doubled keyed
Stock GM Forged Rods
Old School Forged TRW Slugs (they were in it when I got it)
Mahle Steel Rings
(Basically I honed it and put the rings and bearings in it and it was in decent shape, could still see cross hatch from previous build.)


AFR 265 Heads - partial CNC
Comp Cams 242 - 254 @ .050 113LS Hyd Roller Morel Lifters

8/71 Dyers Blower 20% underdriven with 2 750HP carbs


The result:
578 ft lbs at 5300
674 HP at 6500 and still gaining... we shut it off at 6500

It made over 500 ft lbs from 3200 +
We left it fat and happy, it was at about 11.5 ratio at WOT

5.45 lbs boost at 6500


I was happy with the result, I was looking for 640-650 on the dyno and hoping for 600+ in the car. We could have easily made 700 on 93 with a little more compression or timing or boost. But we would be testing the limits of the stock block, crank and rods.... and my pocket book!
For a street motor that will rarely, if ever see over 6,000 rpm, I am very happy for what this little rat did.

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Nice nr´s

Nice!

That is going to look good, and be fun

Andy, how much boost are you running?

He said 5.45 @ 6500.

Nice job. Engine looks great too!

I have a 8.75, 441 SBC being built for boost. I't actually was originally going to have the same setup up top as yours.
There was 2 of them being built for a boat.
Mine is going to have twins tho.
Post pics when you get it in the car!

I would be worried with those heavy pistons and stock rods ??

Seems like you're flirting with disaster IMHO but I'm not experienced in how far you can push those components

they will be fine for a low boost deal like this. if he was pushing rpm's up to 7000 or going for over 7lbs boost I would be worried, I know guys running cast crank 454 and 396's with 4.5-5.5lbs boost making as much or more power in marine engines on stock rods and heavy trw or speed pro pistons. even a few running cast and hyper pistons up to 4.5lbs with no issue on pump gas. roots blowers are not as hard on parts like N20 can be. and if the rpms are kept in check no real issue's will be had.

Sorry, missed that.

Stock BB rods are pretty durable, so are the old TRW forged pistons. My old 427 I had years ago had a set of old TRW's that were domes had em cut to flat tops ran 9lbs boost with no issues.
Nice job on the mini rat.

TRW/Speed Pro were THE piston to run for the last 50 or so years. Yes, now there are newer more modern options but the TRW's are PLENTY durable!


To the OP, nice job on the build and doing something a bit different by sticking with the 396/402! Betcha' everyone and their grandma told you to go bigger.

Nice build!

Very nice build and numbers!! Sincere congrats.

BTW: Has anyone ever used the AFR 265 heads on a normally aspirated build?

I realize the bore on a 396/402 isn't ideal and getting pistons/compression right could be a challenge......but there are a number 396/402s out there just begging for modern heads and a HR cam, IMHO.

Not to get off topic.......

5.5 Lbs

Thank you

and x10 on being told go bigger.....LOL.... I had these known good parts, so for me it was a matter of not wasting the parts and spending extra cash. And for what I was looking for, this is perfect, was looking to keep it under 700 HP. Very safe and very streetable.