401 pistons

[casey]

Hey folks. I finally have a 401!!!
Now I need to find some pistons. I have done a search of the net and found there are not as many options as in the past.

I want to build for wheeling, not drag racing. So I want durability and low end power. I would also like to keep the compression ratio down in order to run lower octane fuel. Simply because I don't want to have to count on the local stations in E. BF nowhere having super.
Someone (I cant recall who or why) said not to use the Keith Black pistons. I've used them in SBC builds and have been very pleased. KBs are wicked expensive to boot.
I already have the rebuild kit and RV cam. I'm going to run HEI and GM TBI on it. Stock manifolds, intake and exhaust (non A.I.R.).

What would be a good source for an .030 over piston set?

Any suggestions?

Thanks

[Dusty]

I have done a search of the net and found there are not as many options as in the past.

There are more options now than there have been in quite a few years. KB makes a good piston, Speed pro. - you can ge the speed pros through fastengineparts.com , mad-dog racing two in the same there but also summit has been having good prices.

the stock replacement or forged 8.5:1 pistons that speedpro makes work well, if you put 51cc heads on instead of your 58cc heads you should find yourself close to 9:1+ a bit derepending on a few things

Use a performer intake. and id probably say the Holley 670 if you opt later to not go with fuel injection.


i know you already have the engine kit and rv cam. but mos tthe rv grinds in the kits tend to be smaller than stock.

I have really liked the H262XE cam from comp but i will say that the howards .479 lift 222 dur @.050 with a 114 lobe seperation has been great in a trail jeep cam idles at 500 rpm tons of torque off the line all the way through. all it is, is a glorified rv grind not far off from stock specs. it works really well with fuel injection. stay with a 112 or 114 lobe seperation for a trail rig it keeps the idle and torque curve smoother as well it keeps vacum up for the accessories and for the fuel injection.

i was running a .512/.512 lift cam with a 274 adv dur 226 @.050 dur and a 112 lobe sep and it never ceased to amaze people how it could idle along on the trail with no low end grunt isses and then still manage to come alive on the sand dunes when it needed too. it worked fairly well with the fuel injection though with a carb ive been alot happier


DD

[happyhoppy]

I purchased a set of used .030 TRW L2308 forged pistons on ebay a year ago thinking my 401 had to go .030 over - but it was okay at standard bore. Had them checked at the local machine shop and they assured me they were fine to use.
They were advertised as very, very low mileage and they appear to be just that.
$125.00 and I'll pay the shipping.

Can send pictues if you like.

(Believe these are 10.5:1 compression.)

[82Waggy]

I'm using the KB 354's in my 401. I'm unshrouding the valves to open the chambers up to about 65cc's to keep compression down to about 9.1:1. With the standard 58cc heads compression will be up near 9.7:1 with these pistons.

Watch compression height with whatever piston you choose and shoot for a zero deck height with an .045 thick head gasket for good quench. This will help reduce potential detonation - as well as other benefits.

Hey Dusty, aren't you running fairly high compression with that custom Crower 222dur cam?

PS: The troughed head style of that Speed Pro piston is really lousy for quench and flame travel. Unfortunately, off the shelf choices are limited. The KB requires bushing the rods to run their .9272 diameter wrist pins.

[a440plus6]

I've had real good luck with the Kieth Black Hyperutectic pistons on Mopars. Not forged but imho.....you don't need forged. They are HEAVY.

[Dusty]

yes

i was at 10.2:1 with the edelbrock heads now with cast iron heads im running 9.8:1 roughly and still no gripes.

and yes the KB's have a much better design than the Speed pros but price wise the forged speedpro's were $360 to my door

[casey]

Thanks for the input guys. Dusty, I would like to put new pistons in. Thanks for the offer.
I also like the idea of 9:1-9:7 compression ratio. 9:7 being high.

Keep it coming.

[Dusty]

what did i offer?

[casey]

what did i offer?

Right!

My bad...happyhoppy..thanks.

[donwag]

My last 401 build I used stock style pistons and Eddy heads to get the compression ratio to just under 9. Very good torque curve. It runs great on pump gas and plenty of low end power.

I am building another 401 and I am going to use the Keith Black pistons and stock heads with the chambers opened up a little to get to about 9 to 9.5 compression ratio.

Key is, you have to match all components to your desired use. Don't just select pistions and forget about how they will work with the rest of the engine.