Advice on building a stroker for my 75 l48

[MTC_75vette]

I have a 1975 l48 with a fresh top end rebuild mostly edlebrock parts. This winter I planned on buying flat top pistons bringing my compression ratio to 10.5-1 . I been told I should make it a stroker which will give me much better performance. I briefly looked at stroker kits and found that they were affordable but I was curious if it was a simple as buying a stoker crank,pistons and rods or if I would have to replace other parts as well. If anyone can provide me with some info i would appreciate it greatly thanks!

Mike

 

[JohnZ]

You'll also need to do some clearance grinding on the block for the rods, and you may have to use a small-base-circle cam, depending on the configuration of the rods.

 

[glen242]

The newer stroker kits with ARP cap screws will eleminate, for the most part, any need to use a small base circle cam or grind on the rods. You will, however, have to grind on the block - bottom of certain cylinders and oil pan rail.

 

[rgtrough]

Hey MTC, don't be concerned about the block clearancing issues that arise from stroking your stock 350. Any compentent engine builder will know about it. It also is not a difficult procedure if you plan on doing it yourself. I would highly suggest using a quality, forged rotating assembly that you have internally balanced. Even though you can buy "balanced" assemblies, I have heard many stories of unbalanced "balanced" assemblies. If your objective is a tire shredding fun driving car than a stroker is what you're looking for.

peace Bud

 

[Hib Halverson]

Stroker kits can be a good thing, depending on the quality of the parts and the rpm range of the engine.

Be careful though, 10.5:1 is right on the ragged-edge as far as iron head engines and detionation goes. You're going to find that in warm or hot weather you're going have to retard timing or use a little racing gasoline to kee the engine out of detonation. I think a better choice is the stroker kit but 9.75:1 compression.

 

[MTC_75vette]

Stroker kits can be a good thing, depending on the quality of the parts and the rpm range of the engine.

Be careful though, 10.5:1 is right on the ragged-edge as far as iron head engines and detionation goes. You're going to find that in warm or hot weather you're going have to retard timing or use a little racing gasoline to kee the engine out of detonation. I think a better choice is the stroker kit but 9.75:1 compression.

Thats for the input as much as I would like a stroker I think I am just going to keep the motor how is and put flat top pistons in as planned.

 

[Ed's 1970]

Keep in mind with the internally balanced kits, more clearance grinding may be necessary due to the larger counterweights on the crankshaft. From what I have read lately, it is better to install an external balanced kit due to less grinding on the block. There are water jackets near where u have to grind, one has to be careful with, u definetly do not want to grind too much or you'll ruin the block. A small base circle cam may also be necessary, so do not rule that out either.

Have u thought about going with a big block?
A 427 and 454 are really nice motors which are designed to take those larger 3.75" and 4.0" stokes and there is room for growth after that even.

 

[Art Jett]

I'm running a 383 stroker with a 218,224 duration-.462-.469 lift @ .50, 110 degree lobe separation cam, 1.5 roller rockers on Edelbrock Performer RPM heads, aftermarket TPI, a 700R-4 tranny and 3.70 rear gears. It's got 9.8-1 compression and runs great on mid-grade gas. It's so much fun to drive I've put over 11000 miles on it since July '07 and I have a company truck to drive to work every day. Check my pics for a shot of the engine, can't seem to get a pic to show in a thread.:confused

 

[topless82vette]

You could buy what my friend did. It's a 3.80 stroke crank shaft to use in a 350 with stock bore and rods that makes it a 383. Chevy uses this forged crank in there ZZ383 it is made by cola (I think is the company) However I believe it is only made for a 1 piece rear main seal but maybe there is a 2 piece version of it as well. Or simply buy a 1 piece rear main block and build it don't see why you internals wouldn't work in it.

He however is taking his a few steps further and building it into a 396 stroker thats supercharged.

I do know with this 3.80 crank in a stock 350 block a few things have to be clearanced. One I know for sure is the oil pan rail and I think with more than stock length rods you have to notch the bottom of the cylinders. I am not sure of the price of this crank shaft he bought his for 750 shipped from another guy but it was brand new.

 

[CNC BLOCKS]

You could buy what my friend did. It's a 3.80 stroke crank shaft to use in a 350 with stock bore and rods that makes it a 383. Chevy uses this forged crank in there ZZ383 it is made by cola (I think is the company) However I believe it is only made for a 1 piece rear main seal but maybe there is a 2 piece version of it as well. Or simply buy a 1 piece rear main block and build it don't see why you internals wouldn't work in it.

He however is taking his a few steps further and building it into a 396 stroker thats supercharged.

I do know with this 3.80 crank in a stock 350 block a few things have to be clearanced. One I know for sure is the oil pan rail and I think with more than stock length rods you have to notch the bottom of the cylinders. I am not sure of the price of this crank shaft he bought his for 750 shipped from another guy but it was brand new.

Using a 3.800 stroke crank requires a custom piston or you would need a 9.025 deck which is very hard to find from what we have seen most decks to get them square end up being around 9.015.

Using a 3.750 Callies Compstar which is a nice peice as far as sizing, straightness and round journals compared to the Eagle and Scat cranks. And they run 595.00, The Scat 6 inch rods I-beam with the 7/16 bolts are a good choice and the Maule pistons are ring kit are good as well and they use no ring spacers with thier 1.125 compression height pistons.

Here is a build we dynoed a few weeks ago for an 86 Vette
http://www.chevelles.com/forums/showthread.php?t=236517

 

[CNC BLOCKS]

I have a 1975 l48 with a fresh top end rebuild mostly edlebrock parts. This winter I planned on buying flat top pistons bringing my compression ratio to 10.5-1 . I been told I should make it a stroker which will give me much better performance. I briefly looked at stroker kits and found that they were affordable but I was curious if it was a simple as buying a stoker crank,pistons and rods or if I would have to replace other parts as well. If anyone can provide me with some info i would appreciate it greatly thanks!

Mike

Mike
If your going to build a stroker make sure your using a good 4 bolt that has been sonic tested for cylinder wall thickness and our stroker build that are gong to be over 475 foot pounds of torque and 425 horse we either use a 4 bolt replacemnet caps or if its a 2 bolt we go to splayed caps.

We get a lot of calls about 2 bolt caps walking aorund not so uch because of the HP buththe added stroke which does side load the caps more and don't be fooled by thinking studs will take care of the problem cause its only better hardware and does not make the cap stronger in any way shape or manner as its still a grey cast cap used in engines under 400 horse with 3.480 strokes and under.

Now the 400 two bolt uses a 2 bolt cap but GM used a wider register for extra stabilty and strenth.

Good luck with your build. Carl

 

[Ed's 1970]

I don't know if anyone has mentioned this yet, it would be a good idea to zero deck whichever block u get, it makes the motor less detonation sensitive and makes more power. So, this would pretty much eliminate using that 3.80 stroke crank unless custom pistons.

 

[CNC BLOCKS]

I don't know if anyone has mentioned this yet, it would be a good idea to zero deck whichever block u get, it makes the motor less detonation sensitive and makes more power. So, this would pretty much eliminate using that 3.80 stroke crank unless custom pistons.

On 95% or our builds we shoot for zero deck and any shop boring of the decks the block sould be squared first as we have seen a few blocks ruined by boring of an unsquared deck.