[brit56belair]

HI just purchased a 400 short block id no is 3951511 on the pistons is L2352-30, does the 30 mean 30 thou oversize or 30thou deck height. stroke is 3.75.
so im think they are not twr 377 destroker pistons, any idea what cam i could use with a set of chevy cast bowtie heads 64cc chambers.
lastly what compression ratio,would this give me.

come on lads help a brit from across the pond.!!!!!!!!!!

[poncho62]

welcome...moving this to the engine forum....you will get more responses there.

[BOBCRMAN@aol.com]

The .030 means it is an oversize bore piston. As for cam, you need to state what the use of the vehicle will be and car specs that it will be in..

[brit56belair]

1956 chevy belair stock trim. 3.75 gears th350 with heavy duty kit stock converter.(i tow a caravan & have kept stock converter).
the car at present runs a 350ci block with the steel bowtie heads and a edelbrock performer rpm cam.headers 750 dp holley msd 6al and dizzy.

with this cam the car boggs of the line i know this is due to the converter and wieght of the car. car still ran 13.74 at 101 mph

what cam would u recommend for the 400 block head combination.
and what compression ratio would the heads give me

thanks Nick

[MI2600]

Nick,

I'm running the same piston with 64cc heads and I'm right at 10:1.

[farna]

A 350 with a stock converter, towing, so I'm assuming a mild cam and maybe 6,000 rpm tops. The bogging is more likely caused by to much carburetor. Your combo would like a 600-650 cfm so much better, though it might not rev quite as high. How much driving do you do over 5,000 rpm? A smaller carb will produce snappier acceleration and lots more low end torque than the big one. That's one advantage of a Quadra-Jet carb -- it can be big as far as total cfm, but still have small enough primaries for good low end torque. Over carburetion is a common problem. If it runs good with a 600, 750 has to be faster/better, right? Not necessarily... In your case the only way to get good results with a 750 is to go to a higher stall converter so the engine winds up a lot more before trying to move the car and caravan.

Looking back at your times you're, you're running darned good with a stock converter! You would probably run the same time but a bit less mph with a 600-650 cfm carb. The smaller carb should improve your 60 and 120 foot times, but hold back on rpm and speed a bit further down the track.

Oh, for you US guys, "caravan" is British for "camper"!

[techinspector1]

Your final c.r. will be dependent on the gasket used and deck height. Here are a couple of computations...

833 in the cylinder
64 in the chamber
12.5 in the piston
9 in the gasket (0.039" compressed x 4.200" bore)
zero deck
10.74:1

same with the piston 0.030" in the hole at TDC
10.05:1

[brit56belair]

Thanks techinspector one for the compression ratio just what i want to hear.
what rev limit would this take with standard rods.
Any ideas on a cam.


Farna your right i ran a edelbrock 600 performer last year as well the 750 dp. but found it weak when doing burnouts.time wise lost about 5 mph and down to 14.2's.
just couldn't get the the car to idle the primary jet springs wouldn't stabilize when shifted into park on idle. tried all springs without any joy.shame the carb was great driving day to day with good mpg.

Hoping a different cam with the 400 block will sort this out.

sorry still wasn't clear on usage, mainly street not too worried about gas millage with six trips for weekend racing. open headers and play with the jetting etc.

thanks guys great info back just what i need.
Not many of us using 400 small blocks over in the uk, we mainly go straight to big blocks for more power.

I wanted my 56 chevy belair to run constant 13's with a small block . just got to get in the 12's, then tow the CAMPER (caravan in blighty) home.

Thanks Nick

[Bob C]

I assume you have already converted to side motor mounts. If not the larger 400 balancer won't clear the 56 front mounts.
Bob

[tornado-tech]

Something around 230 duration works very well in a 400. It will work very well with what compression you probably will have. It will have good around power for you with a small lope to it.

[brit56belair]

thanks bob yes already have side mounts. left the front mounts on as well but it sounds like there coming off.

[brit56belair]

what about a comp cams xe 268 hyd anyone using one