Building motor, looking for 7300ish shifts, prob 10.7 or so compression. Worried about being able to run enough duration/lift to make power that high with the pistons being flat tops.

Opinions? or is this something that is regularly done

 

dam prob shoulda posted this in internal engine

 

7300 is kinda high for stock rods. At least swap out the rod bolts, thats a must. Also, if you want that 10.3 compression with the stock bottom end, you will need to mill the heads, which will really kill your ptv.

I just put LS3 heads on a LQ4 this summer, check out this thread I had going. I had some PTV issues.

https://ls1tech.com/forums/generatio...close-run.html

 

planned on re ringing/new bolts in the shortblock throughout. And knew they had to be milled but thats where Im gettin worried bout ptv since I do want to spin some rpm

 

Well, if you are pulling the bottom end apart, take the pistons in to get fly cut. Also this where someone mentions resizing the big end of the rod due to changing the rod bolts.

 

I have an LQ4 with LS3 heads with a .040 head gasket on it. My cam is spec'd by PatG and he says I should have no issues with PTV clearance. I also threw some molding clay in there and I was greeted with a good amount of clearance from whats there.

Remember that LQ4 has dished pistons so you get a little wiggle room. IDK how many times the stock bottom end with like that high of an RPM but hey it'll be fun to try. If you're gonna take the bottom end apart I hear it's a good bet so get everything balanced. GM does a Meh-so-so job on the balancing so there's some improvement there. Also it would be a good investment at this point for ARP hardware anywhere you can afford.

 

arp hardware will be throughout. Original goal was 7k shifts but Im leanin towards a faceplated tranny so why not spin it

 

For now I'll be happy with 6900 shift points

 

Even though the LQ4 has dished pistons, the large L92 valve needs a relief that extends out closer to the cylinder wall. You can run a wider lsa to give enough clearance and it'll push the powerband high enough, but with that compression it will be a bit soft down low.