Going to do a top end rebuild just for the hell of it, with 150k it can't hurt. The car's been raced every weekend for at least 3 years now so I know I want to do all new gaskets, and valve springs since it's been over-revved a couple times. I figured I might as well freshen up the heads. Then I got to thinking about a different set of heads while they're off. What have you guys done with different heads. Notice any power gains with stock cam?

 

Stock cam? NOOOOOO! Say it isn't TRUE!

A new bumpity stick (compared to stock) would probably provide more HP/$$ than any set of heads you could find, unless you steal them. Even then, any head you get will want something more than the .384 lift of the stock cam.

A cam, decent springs, retainers, and good rockers are probably money better spent than any small bore heads you'll find. If you're really set on getting heads, World S/Rs can be an improvement. Don't forget to get a cam with that.

BTW - Did I mention that you should change the cam?

 

Didn't want to get that far into it, it's just a daily. Figured I'd either put the $$$ into the stock heads to freshen them up or put it towards a better set of heads. If it gets a cam, it's going to be a small one for sure. I don't want to mess around with any tuning. I'm just weighing my options before I start anything. Are there any cams out there that will work with the stock heads and get the car into the 13's? It's been a 14.40 as it sits.

 

The LPE216 cam
http://www.lingenfelter.com/store/lpe-74216.html
should work well with your engine with out a lot of special mods or tuning, but you'll still need to freshen up the heads. My husband has worked on a few LB9 heads. If you were closer I'd just tell you to bring them by.

 

I'm good on the machine work end of things I work at an engine shop, just never tried messing with an LB9.

 

you will NEVER see 13s with that car regardless of what heads you run unless you change the cam. Why the heck are you doing all that work and sticking with a lame cam? Honestly I would pull the motor and at least re-ring it and put in new bearings. With 15000 miles, a hone job and polishing the crank is pretty good insurance in my book. Your car has a Mass Air Flow sensor, MAF cars are quite tolerant of modifications. I am running a pretty lumpy cam in my 305 and I have no issues, and I still get 26mpg on the highway. Check my sig for my suggested cam and head choice. If you are not going to change the cam, I wouldnt even bother pulling the heads or anything, it doesnt sound like it needs it.

 

Yeah, I'm going to re-ring a motor that's only got 7-9% leakdowns Mileage means nothing. And it still carries 45psi with warm oil at idle.

What heads are on your car? Not in your sig.

I want to freshen up the heads just because of the mileage. New valve springs, valve job and I want to check for any bent valves since I know it's been over-revved a couple times. It's got a miss that I can't find and it breaks up in the upper R's now so I think I've got a burnt valve or two and the springs have to be weak. I'll probably replace the valves, do a valve job, do a little bowl work and hit the chambers a little bit.

 

clean off your spectacles dude, my sig says "ported vette heads"

which mean I have mildly cleaned up, gasket matched, and polished aluminum L98 heads. They are #113 castings off of a 90 corvette. the gain in midrange power was pretty noticeable.

 

How does your car pull from 4500 to 5500rpm?

 

from my dyno graph the engine makes 215hp at 4200, and 220 at 5200. with a peak of 230 hp at 4400 and 4800. It makes 225 at 5000. The engine is pretty much done making power by 5000.

The torque is as follows. It made 260ftlbs from 3000-4600 with a peak of 280 at 3800 and at 4000

As can be seen, this engine has a quite broad power curve. It is a good street motor and has good torque and power at most rpms. All numbers are at the rear wheels with coolant temp at 220 and ambient temps around 90. At the time this car was also equipped with an automatic and 2800rpm stall converter. On that day with ambient and coolant temps what they were the engine was making roughly 300hp and 360ftlbs.

 

Thats not a lot of fall off...5hp from 5000 to 5200? That aint bad at all.

Now no offense bro but I dont think coolan and air temps make a 70 rwhp difference...

 

He's talking about wheel hp vs flywheel hp I do believe..

 

Ahh that would make more sense

its late and the wife and I just got done having some fun so I probably didn't have proper bloodflow to my brain yet

 

yes the 300-360 were flywheel numbers with a 22% loss which the dyno guy told me was correct.

The engine pulls a little past 5000 but you can tell it is about done up there. It is nothing like the other stock 305 i rode in. it has been so long since i rode in a stock 305 car i forgot how bad they die at 4800 with all the stock parts. My engine feels like a NASCAR engine compared to a stock LB9.