87MagnumII

I've got a 350 now and my rear main is leaking because I had to sleeve the back of the crank and it never sealed up correctly. I'm gonna pull it this winter and put in a new crank and seal. Instead of going standard I was thinking about a stroker crank and make it a 377 stroker. I would like to do a 383 but really don't have the time or money to take the whole engine apart right now. Wouldn't take much to roll the new crank in and gain a few extra cubes and stroke. All other things being equal, will I see a slight increase in speed with a stroker crank?

Also wondering if I would have to clearance the block for the crank if I did decide to stroke it.

Mr Maine

I would say that if your making about 1hp/cubic inch then you would gain around 30hp and 2 or 3 mph. Just a guess.

To put the stroker crank in you need to clearance the block, check rod clearance to cam and possibly grind the rod bolts a little.

Also remember you will need new pistions with the correct pin height which basically means you need to tear down the motor.

Wes Burmark

You will have to pull the motor. As mentioned above you need to check for rod bolt clearance and do some grinding on the block. You will need either shorter rods or different pistons. You will probably get the most value by buying a stroker rebuild kit from one of the vendors. I would suggest a roller cam, upgraded heads and intake while everything is apart. You are looking at probably 2-3k in parts plus some more bucks at the machine shop. On the positive side I bet you will gain 5-8 m.p.h. and have an engine that will go about 800 hours with proper care, good oil, and an oil cooler.

87MagnumII

Already running an lt4 hot cam, 1.6 roller rockers, vortec heads, performer rpm intake, 9.8:1 CR with forged flatops, 650 demon carb. The rods are stock gm cast iron from a 1997 truck.

Wes Burmark

The LT4 cam is a Crane 2032 (I believe) and has a recommended RPM range of 2000-5500. I was looking at a Crane #109671 which has 2 degrees more intake and 4 degrees more exhaust duration at .050. It also has 509/528 lift compared to 452/465 (but then you have the 1.60 rockers). The recommended r.p.m. range is a little broader at 1600-5800. I would think your current combo would LOVE an increase in cubic inches. You would probably wind up with an easy 400-420 h.p. Sweet!

Mr Maine

The LT4 hotcam is a gm grind and has .525 lift with 1.6 rockers and .492 with 1.5s and 218/228 duration at .05 lift. Maybe crane made it for GM?

87MagnumII

kinda what i was thinking but dont know if i feel like taking it apart to do it. i just built this thing 2 seasons ago, may just build another short block in my spare time and swap the cam heads and intake over from the current setup when im done with the other.

Trash

Just did an EFI 377 stroker (standard bore/400 crank) and was very pleased. You will notice the extra torque with the stroker. As others have noted the extra 27 cid is roughly 20-30 hp. Rods and thus pistons also become an issue along with the clearance items that need to be addressed.

Depending on how core shift is in the block there are varying degrees of clearance needed around the oil pan mating surface on the block, potential cam interference issues and rod bolt issues.

Regarding rods you could go with 5.7" or 6.0" rods. Pros and cons to each.

There are plenty of stroker kits available. The selection of standard bore pistons for a stroker setup is smaller than that of the 383 variety but JE/SRP has some. In addition you'd want to get the right piston to mach your combustion chamber volume to tweak the compression where you want it.

One last item, with the extra displacement it will bring the peak HP rpm down a little which is not a bad thing, but it would also allow you to cam up a little if so desired.

Good luck and let us know how it goes!