What I have
1987 Formula
1990 L03 Engine
Edelbrock Performer RPM intake
Edelbrock 600cfm carb
Edelbrock Pro-Flo air cleaner
2600 rpm torque converter
Flowtech shorty headers
No cat
Flowmaster 80 series muffler
Rebuilt transmission with shift kit (don't know the specs)
KYB struts and shocks
All new suspension
New axles

The rest of the car is stock specs but most of the parts are new like timing gears, balancer, all cooling is fairly new, fuel pump, steel braided fuel line, etc...

From what I have learned on this site the L03 engine has a roller cam and the heads have swirled ports.

What I want
My car runs great, but I would like to replace the cam both for performance and of course sound. Whenever I upgrade parts I have been doing so with the idea that I want my car to be quicker, not necessarily faster in top speed. New gears are definitely in the future. I will be getting an Auburn 3.73 put in. The heads are in great shape, I really have no reason to do anything with them. I know a lot of you want to tell me they suck or that they will give me less HP, but really, they are in great shape, the entire engine is. So for now the heads stay.

The question I have is, what cam would give me a quicker performance, and a sweet sound, will work well with L03 heads AND work well with better heads later on. If I lose like 1 or 2 mpg on mileage then that's fine, but really no more than that. I already know the new gears will do that alone. Also, should I do rockers and springs too? Or just the cam, lifters and push rods?

I had a 69 chevelle with a 350 I put a Crower RV cam put in once. That made a HUGE difference. I see Crower has hydraulic roller cams. Any opinions on Crower? Also, I don't know what lifts or durations are good and good for what.

Thanks

 

Ask and ye shall recieve. These are the most popular cams for the L03.
https://www.thirdgen.org/forums/tbi/...-synopsis.html
All is explained here.

 

Awesome guide. Thanks. I understand the lift and duration but what is the other number? The LSA? What is that?

 

Never mind, I saw what it means, and that guide is great. Thanks.

 

The thing with an LO3 is that what cam works well with one becomes pretty much irrelevant when you get rid of the TBI…, then it’s just another carbureted 305.

 

It's not TBI anymore. I took it from a 90 and put it in my 87. Took the intake, distributor and TBI off and replaced it with the parts listed above.

 

that was exactly my point...

With that combination of parts I think that your limitation is going to be what the heads will tolerate without machine work, which I really can't answer, but if it was me I'd be looking at something in the range of the comp extreme series, about 224/230/110 (translate to something with similar numbers if you’re not running roller lifters) or the lunati 60102 or 60103 (again, translate to something with similar numbers if you are running roller lifters, FWIW, the lower lift of most flat tappet cams might help getting around the limitations of the LO3 heads)

 

I'm still waiting to talk to someone at Crower but if they don't have something I like then I will be going with this one...

GM Performance Parts LT4 Hot cam 24502586
218/228
0.492/0.492
SLA 112
$199.99

If they have something as good, even if it costs up to $100 more then I'll go with a Crower. If not then I'll be getting the GM cam.

I shopped around quite a bit over the last couple days and talked to a few people and that seems like the best way for me to go. Then I'll either have my valves re-seated and new springs put in or just get another set of heads. I'm thinking 192's. Either way should be fine. Though a different set of heads would be better because porting my heads alone won't do crap due to the small valves. Even if I went with new valves, porting, springs... I'd spend less getting another set of rebuilt heads that are already there.

Here's a couple other cams I was considering. Any one of these should be fine, trying to keep the durations no more than 230 so as not to affect vacuum and the lift no more than .500 so it's not too much stress on the springs and studs...


COMP Cams 08-413-8
220/224
0.474/0.474
SLA 111
$259.95 Summit


Lunati 50143
219/227
0.471/0.48
SLA 112
$302.69 Summit


Edelbrock Rollin' Thunder Performer-Plus Hydraulic Roller 2209
212/222
0.462/0.479
SLA 112
$406.39 Summit

 

Out of those choices I like the lunati cam the best (sorry, I know it’s the most expensive and you probably didn’t want to hear that). I’m not a big fan of the LT4 Hot cam at all, I think it’s one of the most overrated cams out there that gets used a lot just because it’s cheap. Is there a reason why you’re leaning towards cams with tamer lobe profiles? A more aggressive profile with similar duration numbers will get similar MPG and idle characteristics and make more power at the top end, and either is going to require that you swap springs, retainers…

If you want to use a GMPP cam, I think that the GM 12370846 (222/230/112/509/528) cam is a MUCH better cam than the Hot cam. Similar numbers, similar idle and MPG, but I’ve never seen a hot cammed engine run as fast as cars with this cam.
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BTW, did you get my email about your avatar pic?

 

Actually between the two the GM has a higher duration (not much, but higher) on the exhaust, a higher lift and the lobe sep is the same. As for the GM you recommended, I definitely like the duration, that's where I'd rather be but I was told by a couple machine shops here that I need to keep the lift at .500 or lower, and that's with new springs. Otherwise I'd be looking at a lot more money spent on the heads to accommodate more lift.

Any thoughts? Has anyone here ran a higher lift in a cam with L03 heads with no more than new springs?

 

That was one of my early points about the heads tolerating the lift… with most stock chevy iron heads the retainers will hit the top of the valve stem seal somewhere between .475 and .485” lift. I don’t know of any that will go higher till you get to the mid/late 90’s (LT1’s and LS based engines) and even then the vortec heads are still limited to well under .500”. I’d be very surprised if you made it to .500” with any of them without cutting the valve guides down or at the very least used offset retainers.

 

If you really intend to keep the lift down to where you won’t need to mess with the valve guides, then I’d say the comp cams one that you listed is the only one that will do that and have duration numbers near where you’d want them.

You could also go with a custom grind, for example comp has low lift roller lobes that you could use, but really, if you want to just keep lift numbers low I’d even seriously consider just doing it cheap and going hyd flat tappet, maybe something like the lunati 60102 that I suggested earlier…

You might also want to search for some of mw66nova’s older threads… He’s run some really good times in a 305 powered camaro using some of the older, old school (lower lift), more traditional cam grinds, and has given pretty thorough details on this site…

 

Does anyone happen to know the specs for the L03 heads? I am now considering just changing my heads and the cam at the same time. Would the 10088113 heads work on this engine? I see a set on ebay never used for a good price. I also saw these...

http://store.summitracing.com/partde...5&autoview=sku

Any good?

 

YEAH 113 will work . but if you stay stock I would go with a factory lt1 cam. I have seen good gaines with a 305 tpi with that set up.I did a 88 iroc with a 305 just fresh motor stock heads. slp runners on it and normal bolt ons and the car ran low 13.0s with a lt1 cam in it. made tons of torque too. i know you dont have the same intake which is better but a good choice for stock heads and cheap of course. I have 3 here actually. heads wise afr 180s would be the best choice for growing into with many combos.

 

Ok I have everything picked out to do the upgrade, but I have one last question. For the 305 should I get 58cc, 67cc or 76cc heads? I know the L03 heads I have now are 58cc and I use low octane fuel. I read where others are saying if I use 67cc heads I would need to use higher octane fuel, yet if I use 76cc heads I can use lower octane fuel. If that's so I just don't understand since I am using lower octane now with 58cc heads, why would the next step up require higher octane then the next step above that mean I can go back down to lower octane?

Or am I just misunderstanding everyone?

Also, where is the better performance? 58cc, 67cc or 76cc? By the way, these are the heads and cam I'm looking at...

http://www.jegs.com/i/World+Products...770-1/10002/-1

http://store.summitracing.com/partde...8&autoview=sku


Thanks

 

I would go with the 58cc heads, the 67 and 76 will lower your compression and there is no need for that.