331 or 306

[mike90lxII]

Wich should I go with? Reasons...

With good rods and pistons and a main support how much HP os a stock crank going to take. If I keep the RPM around
6000-6500 will it last awhile?

[07ROUSHSTG3]

IMO you might as well just go for the 331, you are really not losing any reliabilty with the 331 nor does it really cost anymore to go that little bit bigger.

[CPonyGo]

I just went 347 and am happy as can be- just hit the 500 miles and it runs strong- lots of torque and lots of hp with a nice port job on the TW heads...

306 is just a 30 over..the others are strokers and a 30 over..I was really happy w/my 306 as well but the stroker is a fun factor I can't wipe off my face...lol

btw- maybe this should go to the ford forum

good luck

[mike90lxII]

I just went 347 and am happy as can be- just hit the 500 miles and it runs strong- lots of torque and lots of hp with a nice port job on the TW heads...

306 is just a 30 over..the others are strokers and a 30 over..I was really happy w/my 306 as well but the stroker is a fun factor I can't wipe off my face...lol

btw- maybe this should go to the ford forum

good luck


Yeah, But I am running a S-trim. And the former motor put right around 450 to the wheels and a ton of torque.

[WickedSix]

With the relatively short stroke of both motors I think either one would be well suited to use with a s-trim, the rotational velocity of the crank wouldn't be increased enough to place tremendous additional loading on the bearings with the power number you seem to be looking at. Me personally I like the lil extra grunt sound that comes with the stroker motor too :thumbsup

[BOSS LX]

A 306 is easier on stock fuel lines.

[HRSEPLA]

If you are still using a production block, do not waste your money on stroker kits, just use a stock rotating assembly, the block is the weakest link, the rods, crank, and pistons will almost always outlive the block.
Otherwise you will just have an expensive pile of parts laying in your main girdle.
You will still easily meet your power goal on pump gas.

[mike90lxII]

If you are still using a production block, do not waste your money on stroker kits, just use a stock rotating assembly, the block is the weakest link, the rods, crank, and pistons will almost always outlive the block.
Otherwise you will just have an expensive pile of parts laying in your main girdle.
You will still easily meet your power goal on pump gas.

Ok so I can get a shortblock from D&D motorsports for around $1800 with the main support. It has stock crank and rods with forged pistons. This should hold up? The car has a x-cam and windsor jr heads..

What rpm lvl is safe with that set up?

[HRSEPLA]

That should be fine, 6000rpm is the safe maximum usually, the key to stock block life is keep RPM's in check and do not let it detonate!
What happened to the big blower / windsor combo?

[mike90lxII]

That should be fine, 6000rpm is the safe maximum usually, the key to stock block life is keep RPM's in check and do not let it detonate!
What happened to the big blower / windsor combo?


I don't want to wait on getting the car back together and I really shouldn't spend the money to do a 408 right now. For the amount I drive the car the power it out out was good enough...

[885.0stang]

my bro has a procharger 326? (331 stroker with stock bore) in a stock block from CHP, revs it to 5500-6000 and makes 600 rwhp for about 12000 miles unrebuilt. its all about tuning and how high you rev.

[CPonyGo]

rpmss will let the motor live...didn't realize you were running a strim....

[Prince Valiant]

meh, if you are going to blow it, and you've got a 3" forged crank now that's salvagable, go with a 306. If you need to get a new crank anyways, then 331/347, since the upgrade cost would be about the same as a 306 w/ new crank, provided you were getting new rods and pistons anyways.

The S-trim will only support so much HP anyways, so the final tally will be rather close. Just rpm's it makes it at, and how streetable the engine seems.

[Slow Joe]

408... :rolf I had to...