Couple of 305 questions for you guys.
1. Are the later LB9 motors "roller motors"? (roller cam etc.)
2. Are the heads on the Tpi motors steel?
3. Whats the difference in short blocks between L03 and LB9?
Thanks for the help.

 

yes later LB9 are roller cams (89 and up?, not sure when they changed)

heads are cast iron

I dont think theres any major differences in the short blocks...different cams, intakes, and exhaust...I thinkt he bottom ends are the same.

 

Short blocks don't consist of the intake.

Roller motors started in '87.

 

I know they dont, just highlighting the differences between LO3 and LB9

 

So can I change it to a solid cam and lifters ?

 

probably...may need different heads, I am by no means an expert in this area, naybe Mark, ede, Vader, or RB83 could answer you better. My question is why, nothing wrong with the roller cam, its my understanding it works more effeciently.

 

Iam looking for a 305 that produced the most power is factory trim. We run them in a the West Coast Pro Truck series. I have to run a spec cam and a spec intake carb combo.

 

oh man, I just gotta quote that sorry, I've been mentioned with the likes of those guys, man that made me laugh.


why would you want to change from a roller cam to a solid? I assume b/c of the specs you have to adhere to?

 

'87-up sbc's have provisions for roller cams. The motors that went into cars generally had the roller cams while the truck motors, although they had the provisions for roller cams, had regular hydraulic cams. The short block of an LB9 and an L03 of the same year should be the same. Oh yeah the most powerful 305s stock were the G92 LB9 motors of 90-92 (they had 230 hp). The L69 was the most powerful of the carbureted 305s at 190 hp, but most of those motors didn't have roller cams (only the 87-88 monte ss).

 

I figured you would like that

My dad actually works with a race team that was running trucks in the PARTS Pro Truck Series and the FASTRUCK series here in the southeast. They have to use stock/mildly modded 305s and IIRC they run the roller cam motors, a blueprinted hand spec'd motor with aftermarket replacements of stock equipment (not performance parts, just better made than stock) will easily turn much better RPMs and hp/torque numbers than factory, especially if you have better options for fuel delivery and exhaust.

edit: check out camaro cam specs here: https://www.thirdgen.org/newdesign/tech/techdb.shtml

 

08, you can change from a roller to solid, all you need is to trash all the roller parts, retainer, spider, push rods, timing gear set and chain and get longer push rods, need them anyway with more lift, and a non roller timing gear set up. if you havea flat hydrolic and want to change to a solid all you need is the cam and lifters. make sure your springs match the cam and you might want to get rid of the pull out studs.

 

Thanks guys for all the input. We are kind of limited on the parts we can run. The cam they make use use is kind of weak.
Cam lift: .308"I, .313"E
Lobe Center: 110 Degrees Intake
Duration @ .050: 218 deg. I, 224 Deg. E.

Max valve size is 1.84 intake, 1.50 Exhaust

Holly 4412 2bbl. carb.

Edelbrock #7101 intake (performer RPM) or #7116 w/ center bolt heads.

9.5:1 Compression MAX (most people say 9.3:1 is the max you want to run)

So Iam thinking if I run the newer style motor I'd be better off. The heads are alot better Iam told. Unless someone else can give me a better idea on combos. I really do not know much about 305s. The most power these guys have seen is about 330hp on the dyno. So iam told. Thanks again!

 

I have an 88 and it doesn't have roller rockers, is that ok? Did they come like that, or did some previous owner change it? Thanks.

 

If I missed the statement then ignore me, but if the motor came with a hyd roller cam and you can switch it to a solid lift cam, why not put a solid roller cam in it? MUCH less friction. More RPM. The maintenance of the solid roller is the same as the solid flat tappet, except that in a cam change you don't have to change the lifters on a solid roller, unless one is trashed. Just my 2 cents.


:rockon:

 

The rollers they are talking about are roller lifters for the cam. Roller Rockers are very rare on factory gm engines.

 

So my car is supposed to have roller lifters for the cam? Is that stock cam of mine a "decent one"? I mean, I just got the car a few months ago and it wouldn't even start when I bought it, but the folks on these boards helped and guided me through and now I've got it running beautifully
I've been wondering about what kind of rearend it has, but don't know, or what's the HP on my motor, but don't know either. The previous owner lost the sticker in the console that tells the different codes for the GTA.
Can anyone help me out finding some of these things? Thanks in advance.

 

FYI the most powerful 305s were the 90 and up LB9s (TPIs) with N10 and not neccessarily G92. N10 was dual cats and 3 inch exhaust this is what made the extra power and the 230hp rating. N10 could be had without G92, G92 came with N10.

Just to stir things up the 1990+ Players Challenge cars supposedly dyno'd at 255hp.

RP.

 

What year is your car? and what kind of mods do you have in it?

David

 

Not sure who you are asking ?

If me, I have a '91 Formula 5-speed with 3.42 posi, dual cats (N10) with 3 inch exhaust -- all factory stuff. I recently switched to a Dynomax muffler as my factory unit was toast.

I have installed pullies, a custom made CAI, and a Jacobs Ultra Team. Pretty basic bolt-ons. My dyno numbers are in the sig. The late model LB9s are pretty hot mine will surprise just about any stock L98 out there.

adious,
RP.

 

Yes Palric, I was asking you, sorry about the mix up. The reason I ask is because mine is pretty stock, except for the gutted cat, Flowmaster muffler, K&N air filter, no emissions, but the rest is stock as far as I know, mine has an original 3" cat back exhaust, no headers just stock manifolds. I've got a friend that has an original dual cat exhaust system that I've been wanting to ask if he would sell me, do you think it would make a difference in HP in my case? Thanks!

 

Guess it gets down to emissions ? If you have to pass local emissions tests then you have to have a cat and if you have to have a cat then might as well go with dual cats if you can do it at a reasonable price.

Oh yeah I made my dyno and track numbers with factory exhaust manifolds. I have headers but they are not installed yet. FYI: it seems that most LB9s with dual cats & 3 inch exhaust pickup about 7-8hp and 12-15lbs torque off a set of headers.

Keep in mind if you go to dual cats you will have to run a splitter off your AIR tubes. Try to get the unit off your buddies car.

adious,
RP.

 

Thanks a lot, I'll check into it. As of emissions, we don't have in in Florida anymore, don't you love it???

That's why we're able to do a lot of changes and still get away with it, at least for now.