Ok, so I've got a 305 TPI automatic 91 Z28, with the 110 speedometer and the 5,000 rpm redline. Now. Everything I've read has led me to believe that this engine came with the peanut cam. I've also got a 92 formula 350. Greasemonkey that I am, I've pulled the cams out of both motors. And what do I find? They are the SAME CAM!!!
They have the same number stamped into the cam: 773 CPC BC 17. I was still in disbelief, so I measured the diameter of the lobes with a set of dail calipers. And the lobes measured the exact same bewteen the two cams!
I'm ... not really sure what to think of this. It goes against everything I have read and heard. What do you guys think? Has anyone else seen this before? Maybe my 305 camaro is just a freak of nature or something?

 

The peanut cam went away in '88 or so. The LG4 did have the peanut cam in it.

 

I had never heard that they put the peanut cam in 91 cars, I thought that the 15 horsepower gain after 89 was because of a different cam and NOT the MAP system. That would make 89 the last peanut cam year, unless they decided to use the leftovers in the tbi cars or something.

 

The peanut cam is found in stock (of course) 86 engines, later engines had a more agressive profile compared to the 86 camshaft.



SSC

 

Youre right, the 'books' say its supposed to be a peanut. I've come across the same thing on a 91 305, L98 cam where a peanut is supposed to reside. The engine had factory gaskets on it. I seriously doubt it had ever been apart.

I really wish the people I'd asked to check their cam lift would do it, I dont think any of the 91-92 TPI cars had a peanut cam no matter what tranny it had.

 

Well, my cam hasn't been measured, but i think it's safe to say that there's no way i'm running the peanut cam and waking up the way i am for as stock as i am...

 

All TBI's have the peanut cam from the factory, and when GM changed to speed density in the TPIs, they put the L98 cam in them.

 

First off- I believe you. Nobody beleived me when I said my 88 TBI 305 had a flat tappet cam and high swirl heads on it, but it did. GM does weird stuff sometimes in changing parts around.

Secondly a question- so what makes for the big HP difference between SAME YEAR 305 TPI motors 5-speed versus automatic trans??? 5-speed is rated, say 215, but the same motor with an auto trans is only 195. Go figure.

What I think happened: GM had a bunch of L-98 cams laying around so they used them in everything the last few years, even if the engine was SUPPOSED TO HAVE THE PEANUT CAM. Only having one cam is a lot cheaper and easier to keep track of inventory, ya know? And ordering 2X as much of one cam grind means they get economies of scale and save money. It's a lot easier to change HP numbers on a spec sheet than cams. GM does this kind of stuff all the time.

 

Yeah, Damon, that's what I'd read/heard: that the 305 autos got the peanut cam, and the manuals got the 350 cam, thus the manual 305 cars were faster than autos. In 91. Granted, all that info came off the internet (here and cz28), so it may not be accurate.
Anybody else got a cam out of a 305 auto? Humor me and post the part number.

 

Here's the cam data off the tech board:
1990-1992

305 5spd / 305 AT
10088155*
.350 .384
179 194
109.0

305 G92 5spd / 350 AT
10111773*
.413 .428
202 207
114.5 (116/-116)

The part number for the 350 cam ends in 773, just like the number I found on my cams. Although the data doesn't specify TPI or TBI, there is no 305 auto listed under the 773 cam.

 

Damon, the SD A4 and non-G92 cars are down on power vs. the G92 cars. G92 cars got dual cats whereas the others (like mine) got the small TBI manifolds and 2.25" cat. When i swapped dual cats on w/ no other changes i picked up 2 tenths and 3mph. Sounds like a true 25-30hp difference to me.

 

Oh yeah, just thought i'd add. So far every SD 305 bin i've seen has had the SAME fuel tables. Doesn't seem to me that GM ever planned to run a different cam in the LB9, it sure as hell would've had a different VE table if so...

 

with your car being 11 years old are you positive this is the cam it came from gm with? the engine could have been replaced under warrenty, cam could have been etc. i will say we've found odd things from gm also, but that is deffinitly odd. i'll run the numbers at work on monday to see what the computer show's.

 

The 1982 Crossfire Z-28 (LU5) had the same cam as the 1982 350 police spec motor. 194/203 @ .050 duration
.390/.410 lift Now thats a whopper!

 

You had a flat tappet cam in a TBI 305? was it from a truck?

This theory could be true, since the Vettes went to the LT1 in '92, they could have been using up vette cams like mad. Who knows, I was always under the assumption that the '91-92 Z's TPI got the L98 camshaft.

 

There have been multiple people saying the 90-92s got the better cam for awhile now. Although all the books/literature say the A4s got the peanut cam. Several people are running some good times on the 90-92s 305 autos with few mods as well. It would appear to be true that they received the hotter cam, guess we can call it official...

 

what relation does the cam have to a peanut?:lala:

 

Well, the motor that came out was for sure the original motor. I checked the part of the VIN that is stamped onto the deck surface, behind the compressor, when I pulled it out. As for GM throwing all kinds of weird parts onto cars at random, I can vouch for that. Somehow my 91 Z28 also got the wonderbar that was supposed to be specific only to the Iroc. Many other 91s got it too.
What I'm wondering is: did my car get lucky and get the 350 cam, or was the 350 cam standard in all 305s by 91?

 

I have heard that the cam in the 305 H.O. is a 350 cam.

 

told you so!!! lol ive been saying this for years!!

 

My scrubber-cammed, high swirl-headed 305 TBI motor was in an 88 Camaro. It's not what was SUPPOSED to come in the car but that's what it came with. Basically, a truck motor 305 TBI ended up in my Camaro. Stuff happens.

Another recent cam situation similar to this.... where GM said one thing but did another was the early LS-1 motors. The FBody LS-1s were supposed to get milder cams, thus reducing their HP. But in the interest of who-knows-what GM ended up shoving the same cam in them as the Vette LS-1 got. Few months later you have a bunch of magazine articles showing FBodys dyno-ing the same number as the much more costly Vette.

I suspect something similar to the LS-1 cam situation is what happened with these different 305s in the late 90s.

 

LB9 & L98' s use cam# 10111773 in years 90-92
L03 use cam# 10088155 in years 88-92

I don't know what book the peanut cam theory cam from, but this info is right from GMSPO's March 2002 DVD.

 

Was it maybe a rebuilt engine from a rebuilding shop? Cause I wouldnt be surprised if you surrendered your roller cam block you got back a tappet cam in a roller block.

 

I agree. My 92 Z28 convt 3:08 rear 5spd ran a best of 14.21 and 14.5 all day. Probably not a peanut cam

 

Congrats, you just proved what we learned a year ago. The speed density TPI cars all have the same 350 cam, regardless of engine size or transmission. The HP difference (205 vs 230) is due to the exhaust, and GM probably fudged the numbers a little.

Now we just need someone with a 87-89 305 TPI to check their cam.

 

That's what I tried to tell everyone.....

 

and this is supposed to be new news? MrJ has been saying this since the time of Jesus

 

I'll attest to that. My friend's 1998 Z28 runs 12.9s in the 1/4 mile with only a muffler and lid. That's as quick as '02 SS's.

 

Oh, my bad. Please excuse me for bein the only dumbass who didn't know.

 

I have a 1989 RS camaro with a 305 <b>TBI</b>. Want me to pull the cam out for the first time in its life? Its as good an excuse as any to do a swap.

 

What I don't get if the 90-92 Z's with automatics had the L98 cam is why the heck did they sill get the 5000 rpm redline and especially the 2.73 gears? The peanut cam was designed for that stuff, not the L98 cam especially in a 305. GM pisses me off with their mysterious crap. Does my '88 GTA have the peanut cam??? It is a 5.7 liter, but it runs out of steam at 5 grand.

 

i have read in "paw" that the l-69 cam and 87 l-98 cam are the same specs.....look under gm performance parts cams

 

ya, i think you should, I have an 88 camaro w/ the 305 TBI, and I'd like to see the stamped numbers on the cam so i can compare it with mine.... when i eventually have the LT1 cam swapped in...

 

The 350 that I got out of a 1992 van, had the peanut roller cam in it.

 

The 350 that I got out of a 1992 van, had the peanut roller cam in it.

My original 305 had the "274" cam in it, standard 350 cam for eternity and 305 HO.

 

Anyone notice this thread is 3 years old?

 

after 1989 all TPI cars came with the L98 camshaft, The L03 engines got the peanut camshaft.

The difference in horspower is in the exhaust system. See back in the day cats were extremely restrictive, so adding an extra converter would definitely relieve alot more horspower.
Also keep in mind the dual exhaust out the muffler.

As far as redline, the L98 camshaft makes power from 2600rpms to 5200 approximately. The difference in redline could be as simple as stronger springs, maybe better hydraulic lifters. etc.

I doubt gm underrated the car to make the G92 package better for no reason. Also remeber the stronger axles, posi 3.45/3.42 as opposed to 3.08's from the second gen G92 cars.

Example: 1989 Chevy Camaro Iroc-Z TPI305 G92 WC T-5 vs.
1989 Chevy Camaro Iroc-Z TPI 305 WC T-5. The G92 wins hands down assuming perfectly equal drivers and other options.

And yes I did notice the age of this thread why? who brings these back?

 

what the freak is a peanut cam?

 

The ridiculously small cam GM put in alot of the 305 cars. Started mainly with the 86 IROC's 305 TPI that got that cam and dropped 25hp from the 85 with no other significant changes (and it's not like the factory larger cam was big, the peanut is literally so puny it's ridiculous)... Was in the LG4 and junk prior to that but that was the first time it was in one of the supposedly hot motors. People generally use the term when talking about the similar roller version of the cam that is still a worthless piece of junk also...

My guess is it's referred to as the "peanut" because it's so small, not sure who actually started that. It's worth about as much as a peanut too, piece of crap...

We still need someone with an 90-92 auto 305 TPI to pull out their cam to prove whether all the SD TPI cars got the better cam, could just be the 5spds (but I doubt it...)

 

I'm gonna guess that it came from the expression "peanuts"

Ahhhh, thats just peanuts

meaning nothing. It's the nothing cam.

 

ill throw in my info. i had alot of people tell me that since i didnt have the g92 option, that i had a peanut cam. but i do infact have the 773 cam. did a 14.4 with hedman headers and slp cat back, otherwise stock, 2.2 60' almost 2 years ago

 

edit dudie has a good point, if your 90 and up you have the L98 cam if you have tpi. the old TPI305/700r4 have the peanut cam

 

psst.

that 91 is a z28 with TPI



the peanut cams are in the TBI cars... like my 91 RS had...