Originally Posted by
lovell
A fellow racer wants to run 20% in his GRP engine...what is the shimming required for the 20%?
He could run it just the way it is from the factory he only needs to add shims if he runs 30% and that would be one more shim to add. I run 2 shims on mine with the 30% just so it does not pit on the piston. If your friend is running 30% and he wants to run 20% he will have to retune the block. I run both the .21 GRP and .28 GRP. I run 6.0 venturis in the .21 for the buggy and a 7.0 venturis in my truggy.
Hope this helps!!!!!!!!
