L31 continue in production as replacement motors and for oil field-gas field work, stationary generators etc. L31 (when in production as OE GM trucks) compression ratio was 9.4:1.I've not seen this directly addressed yet, how does Vortec compression stack up against TBI compression?
Specifically the reason I ask is that I see different starter part numbers listed for my '88 TBI truck than the later Vortec trucks. Reading another thread on here, I saw that high-torque mini starters (and a slightly larger "medium size" starter) were used in some of the later TBI trucks and carried over to most of the Vortec trucks. If one were to have an early starter, would it be wise to plan on upgrading to a higher torque starter to handle Vortec compression, or is the compression pretty much the same between the two?
Today's GM replacement L31 are also rated at 9.4:1.
If ya really wanna KNOW what specs are (including compression) for most GM cars & trucks, simply go to this GM site; there are entirely free pdf for most anything ya might want. There's lotsa details to wade through.
I'm gonna guess here that most TBI motors from eighties & early nineties had relatively heavy OE Delco 10MT starters (direct drive with field coils & pole shoes). Those were superseded by all new & very light Delco PG260 design with Permanent magnets (instead of field coils) and an internal planetary Gear reduction ... that's the starter that is OE on all trucks equipped with L30 (305) or L31 (350).
here ya go ... Very good Remy starter info sheet
chrome-extension://efaidnbmnnnibpcajpcglclefindmkaj/https://autoprollc.com/wp-content/uploads/2016/12/6-RemyTechnicalBulletin_Feb2016_web.pdf
Last edited: