383-396 questions
03-23-2007, 01:59 PM
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383-396 questions Ok, looking to up the Cubes a bit with a Stroker.....I'm at least going with the 383 but have seen/heard of a few guys with 396's in their LT cars...soo I'm not a perfect expert on strokers and never seen a 396 kit, just the 383...what's all invovled in a 396 build??? i'm gonna be boosting motor by means of a Procharger, maybe just some good ol N20 with just uped jets....havn't got that far into the planning phase yet....I do know that the N20 setups tend to used a higher compression and vise versa with Boost.....
03-23-2007, 02:43 PM
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here's the skinny on LT1 buildups.... it all depends what you're looking for. there are quite a few non stroked NASTY LT1's out there in the 355 cubic inch variety as well so depending on your budget don't get super dedicated to having to stroke it....
355 ci LT1:
Bore: 4.030 (.030 overbore with an .030 oversize piston)
stroke: 3.50 (stock stroke)
rod length: 5.7", 5.85", 6"
notes: 355's don't get the additional torque of a stroker motor. upped compression for more power is almost a must. Also a 6" rod 355 has one of the best piston/rod ratio in the game. more dwell time at TDC, more complete burn will usually result in more power. Try to get compression up to about 11.5:1 to 11.75:1. Will still run on pump gas at those levels. Good heads/intake also a good idea... you can use the stock crank but I would at least 2 bolt stud the main caps while you're down there.... good quality h-beam rod as well for bottom end stability.
383 ci LT1:
Bore: 4.030 (same as above)
Stroke: 3.75"
Rods: usually 5.85 or 6"....
notes: 383's will get the added torque from the increased stroke. same deal with compression as a 355. Definitely get a good forged crank as well as rods and pistons. Lunati, SCAT, or Eagle at a minimum. Block clearancing is required for rod bolt clearance but it's pretty minor and any competent shop can do it....
396 ci LT1:
Bore 4.030 (same)
Stroke: 3.875"
Rods: i've only seen 5.85's
notes: again more torque from more cubes and more stroke. block requires alot of clearancing and be careful because you don't want engine man to cut into a water jacket reducing block to garbage. with custom work i think you could use a longer rod possibly but not advisable... i have limited experience with 396's.... i personally like the 383 route since you can always clearance more later if you want the 396 and 13 ci isn't a whole **** ton of an increase....
355 ci LT1:
Bore: 4.030 (.030 overbore with an .030 oversize piston)
stroke: 3.50 (stock stroke)
rod length: 5.7", 5.85", 6"
notes: 355's don't get the additional torque of a stroker motor. upped compression for more power is almost a must. Also a 6" rod 355 has one of the best piston/rod ratio in the game. more dwell time at TDC, more complete burn will usually result in more power. Try to get compression up to about 11.5:1 to 11.75:1. Will still run on pump gas at those levels. Good heads/intake also a good idea... you can use the stock crank but I would at least 2 bolt stud the main caps while you're down there.... good quality h-beam rod as well for bottom end stability.
383 ci LT1:
Bore: 4.030 (same as above)
Stroke: 3.75"
Rods: usually 5.85 or 6"....
notes: 383's will get the added torque from the increased stroke. same deal with compression as a 355. Definitely get a good forged crank as well as rods and pistons. Lunati, SCAT, or Eagle at a minimum. Block clearancing is required for rod bolt clearance but it's pretty minor and any competent shop can do it....
396 ci LT1:
Bore 4.030 (same)
Stroke: 3.875"
Rods: i've only seen 5.85's
notes: again more torque from more cubes and more stroke. block requires alot of clearancing and be careful because you don't want engine man to cut into a water jacket reducing block to garbage. with custom work i think you could use a longer rod possibly but not advisable... i have limited experience with 396's.... i personally like the 383 route since you can always clearance more later if you want the 396 and 13 ci isn't a whole **** ton of an increase....
03-23-2007, 02:54 PM
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stroke on the stock 350 is 3.48 I believe.
Stock bore (4.00") with 400 crank (3.75) yields a 377. .030 over on the bore gives 383 (as outlaw has said). .060 over on the bore with the 400 crank gives 388 inches.
Bottom line...more stroke = more torque. And don't forget the golden rule...'There is no substitute for cubic inches.' That should spark a debate...so let me end it before it gets started..If you pour tons of money is some little cubed motor - yes it will out run a stock big cubed motor...however, if you pour the same amount of money into the big cube motor - it will walk all over the little motor - thus...there is NO substitute for cubes...
Stock bore (4.00") with 400 crank (3.75) yields a 377. .030 over on the bore gives 383 (as outlaw has said). .060 over on the bore with the 400 crank gives 388 inches.
Bottom line...more stroke = more torque. And don't forget the golden rule...'There is no substitute for cubic inches.' That should spark a debate...so let me end it before it gets started..If you pour tons of money is some little cubed motor - yes it will out run a stock big cubed motor...however, if you pour the same amount of money into the big cube motor - it will walk all over the little motor - thus...there is NO substitute for cubes...
03-23-2007, 03:57 PM
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My advice to anyone is to keep the stroke to 3.75 or below because you'll need some $$$$ heads that will breath enough to make good top end with such a long stroke (unless your building a truck for towing). Such a large stroke was fine back in the day for bigblocks because large staggered canted valves are easy to make flow and there was no worry of emissions either. This is of course if your build is on a budget and is for a street car.
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03-23-2007, 10:44 PM
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yeah i was going to bring up the 6.1 rod but they aren't used very often..... that long a rod takes away ALOT of piston crown with the wristpin moved up so high into the ring pack..... not a good idea for a nitrous/FI motor at all... 
