Chevy Impala SS Forum banner
1 - 6 of 6 Posts
G

·
Discussion Starter · #1 ·
What are all the clearance issues when putting that 3.75 crank in the LT1? What size pistons and rods are you guys running?

Much appreciated in advance,
Jeff
 
G

·
Discussion Starter · #2 ·
<BLOCKQUOTE>quote:</font><HR>Originally posted by KLITZKEJA:
What are all the clearance issues when putting that 3.75 crank in the LT1? What size pistons and rods are you guys running?
<HR></BLOCKQUOTE>

I'm running 5.7 rods and a 3.75 stroke crank with 10.5:1 / 4.040 SRP forged pistons. I had to clearance the stock rods, but had no problems with the block edges. Some people do, go figgure. When I originally built this engine there was only 2 reasonable choices for rods, 5.7 or 6.0.

6.0 rods push the wrist pin into the third piston ring and shallower pistons tend to flutter more in the bore. On the upside, long rods dwell longer ar TDC making more torque.

5.7 rods / pistons don't have those issues or advantages, but they are generally cheaper to purchase and are stronger from a piston standpoint. The downside here is excessive sidewall loading. The shorter rod pushes against the bore harder (theoretically) causing shorted bore/block life.

The best solution is to split the difference with a 3.75 stroke and 5.85 rod. These were pretty steep when I built my car, basically out of my budget, as were the pistons. Now they can be had for less than 1000.00 for the rotating assembly.

Hope this is a useful little glimpse into the stroker world.
 
G

·
Discussion Starter · #3 ·
Hey thanx for sounding off Kelly. Where on the rod did you have to clearance?? Anything to do with the rod bolt??? Are you internally or externally balanced???
 
G

·
Discussion Starter · #5 ·
<BLOCKQUOTE>quote:</font><HR>Originally posted by KLITZKEJA:
Hey thanx for sounding off Kelly. Where on the rod did you have to clearance?? Anything to do with the rod bolt??? Are you internally or externally balanced???<HR></BLOCKQUOTE>

I'm internally balanced with the front balancer and rear flexplate both with a fresh and more accurate neutral balance (the factory tolerances sucked.

My rod corners could contact the cam lobes. There was a little bolt interference too.
 
G

·
Discussion Starter · #6 ·
i run a 6" H-beam rod stroker and had little trouble. My pistons are SRP. The fluttering thing is not true. I have had no problems with mine. Here is a pic of my stress reliefs for rod clearance:
 
1 - 6 of 6 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top