im looking for some input on the gm "race grind" cams for the 02-06 l6, the part number for the set is 88958648. ive been searching for anyone that has tried to run them outside of a race only application (or just using them in general) and i cant seem to find anything. things become less clear as many people confuse the gm lsj cams that were available years back as the same thing. those cams were mentioned in the lsj build book.

now the cams in question, as mentioned are set #88958648, and the set (according to the sport compact build book) is comprised of intake cam #88958636 and exhaust cam #88958637. according to the gm build book, this is the specs

intake- 0.499" lift, 247 duration at .050"
exhaust- 0.499" lift, 249 duration at .050"

i see these specs in multiple places, gm claims comp cams 8766 and 8767 is the same cam with a billet core, and their master catalog shows the same specs. i tend to think this is correct, however ive found the cams sold separately (88958636 and 88958637) advertised with the following specs

intake- .46395" lift, 219.1 duration (not specified but im assuming thats at .050")
exhaust- .46194" lift, 221.6 duration

ive only seen those specs from one place, so im a little hesitant to believe them as everything i have read points to the part numbers all being the .499 lift cams.

does anyone have any better info on these? either firsthand, or know anyone that has run them, or even had them in their hands, anything would be great. heck, a forum post or a video of something thats running them would help. im trying sort out if these are at all appropriate for my 944, the specs are a little aggressive for what im after, but off the shelf cams from our vendors are a little small for what im after (and nobody has cams available as comp has no blanks).

 

The car is NA correct?

I dunno the 3500 basic power range I wouldn't personally like just because I like a lot of low end power through the top end. Ive only really messed around with cams in V8 cars and I know that's a completely different giant. Is this the cam you are talking about?

https://www.vividracing.com/-p-15153...SABEgIj_PD_BwE

 

no my 944 is turbo, im running an efr 7670. the car is mostly top end power as the turbo is a bit lazy down low. already have solid lash adjusters and 94lb springs (and ported head, and built bottom end, and supertech valves, and, and, and). i have no problem reving it to 8500-9000, im already shifting at 7800 but the power is leveled out well before that due to the baby cams im currently running (comp turbo grind, 204/200 at .050).

the cams in your link are not the ones im referring to, those are comp 222/224, sometimes called "stage 3" cams. they arent quite what im after, but i had decided on them a few months ago and ordered them, only to wait several months to find out that comp cams has no cam blanks for the ecotecs, and they estimated it would be may before they would have anything ready to ship, and that was before covid19 hit.

the cams in talking about are gm part number 88958648. im assuming they are ground by comp cams, however they are not an off the shelf cam from comp, they have them listed in the lobe catalog and they are able to grind them on billet blanks (if they had any blanks). however more than one online shop has the gm part number in stock, hence why im asking about these specifically.

 

I feel like the build book has a detailed profile on these cams, but it's been almost a decade since I looked at it. I've got a copy that I can try to look at tonight, if you don't have one (I think I have editions 1 and 3). I might be thinking of the GMRacing cams from the LSJ build book, though... and I know Area ran that profile - said that car was a monster above 5k... but not really terrific below that, citing the 9.5:1 CR as part of the problem.

I don't remember anyone on here ever buying and running the GM L61 cams though. I'm sure someone might have, but it might take some serious investigative work to find them.

 

i have the build books (the original sport compact build book, lsj build book, and 3rd edition sport compact build book) and there is also conflicting info from there. for example, in the 1st edition sport compact build book in the 400-600hp section, they list the part numbers for the l61 cams (88958636 and 88958637) with specs of .466" lift and 222 duration at .050, this is close to the one set of specs i listed in my first post. in the very next section, the 600-1000hp section, they list the same part numbers with specs of .499 lift and 247/249 duration. in the 3rd edition sport compact build book they only show 88958636 and 88958637 as being .499 lift 247/249 duraton.

i ran across Area's post in my searching, im almost certain he was running the gm lsj cams that most referred to as the GMR cams. the l61 cams i mentioned above dont have the hex to drive the cam sensor, and Area wasnt running (as far as i could tell) an aftermarket computer. the GMR cams were .441/.437 lift and 218/220 duration at .050, installed at a narrow 109 degree lsa.

im going to find out exactly what they are, at least im hoping to. Jegs showed these as shipping within 24 hours, so i ordered them. they list 88958636 as being .464 lift and 219 duration, and 88958637 as .461 lift and 221 duration (most of the gm parts sites show these specs as well for these part numbers, except for crate engine depot). this is what i ordered. 88958648 is the set, they show those as being .499 lift and 247/249 duration (as do the gm parts sites). everywhere i looked buying the cams separately work out to over $100 cheaper than buying them as a set.

 

Yep, Area definitely ran the LSJ GMR's on the stock computer.

 

so the cams i ordered got put on backorder. id like to say im surprised, but yea.

i may have found a set used though.

 

looks like i wont be putting an end to this mystery. as i mentioned the gm performance cams i ordered got put on backorder and i ended up finding a set of used comp cams 8766 and 8767 grinds. these are 247/249 at .050 and 0.499" lift.