I hope it's ok to put this here. I have a 1986 Iroc-Z which is stock apart from Hooker 2055 headers and a flowmaster muffler. I wish I could say that I have a cat-back, but the intermediate pipe is the original and totally rotted out along the top . I do intend on replacing that lol. This is the year that came with I guess the LG4 cam, so it had 190 hp instead of the 215 that the 1985 had stock. I'm hoping that I have around the 200 hp area from the headers, but I don't hold my breath on that.

This is the cam I would like to purchase (along with new lifters of course):
http://www.summitracing.com/parts/CCA-12-388-4/

I chose this cam because I live in California, and this cam has the E.O. number needed to "legally" have it. Summit doesn't list it, but it does have it. I just want to be able to pass smog.

Assuming I get this cam, which is 0.425 int./0.440 exh. lift, while the 1985 had 0.404 int./0.415 exh. lift, could I run maybe a 15 flat with the headers, assuming I'm running correctly?

What if I were to port and polish the heads as well? What would that do to my time?

I know that dropping in a 350 is the way to go, but I don't want to do a motor swap right now, I just want to fool with the 305. The 305 is in good health, even though the heads have 123K on them. The lower end has 60K or so.

I'd also like to go with some spiral core wires and a distributor upgrade kit, although I don't know it that will do anything at all. I would think that the cam should get me to close to 220 hp, what do you guys think?

 

those upgrades will give you a bit of power, but probably going to estimate a 16 second 1/4 mi time. Problem is poor flowing intake and heads, and 305 just don't make a ton of power...not that you can't get it too.

 

I ran a 15.9 with cheap tires, a burned plug wire, and I forgot what else wrong before I installed the headers.It's suppose to run a mid-15 second quarter stock. Plus, I didn't launch it at all. I'm pretty sure I should be able to get at least a 15.2.

It's the LB9 engine, not the LG4. I was just told that they put that cam in the LB9 that year. My bad, I should have been more clear on what engine I have. I seem to have trouble doing that lol.

Man I wish I had an engine like what's in your profile pic! Thing looks crazy! Props to you.

 

I'm thinking low to mid 15's.

Dan

 

So how can I make it run maybe a 14.8 or 14.9? Do you think between a port/polish, the new cam, and the already installed headers that maybe it could come close to that?

 

I just don't quite understand why 30 or 35 hp over stock in this car wont make a good difference

This is of course based upon the car being a 15.6 second or so car stock, when driven/running correctly, not like my 15.9.

 

that camshaft is a bit on the lazy side, but i like it paired with the TPI intake. the heads are not the bottleneck on those motors, i've used those very heads (416 castings) on a hopped up 305 that ran low 12's.

to get more out of your combo, i'd like to see you pair it with a couple of extras. these won't make more power, but they'll allow you to use what you have better:

-a good quality torque converter. something that sees a flash speed of about 2800rpm
-a 3.23 or 3.42 gear with a good posi unit
-subframe connectors, this will help with parasitic chassis twist. while it's not gonna be a huge increase at the level you're at right now, it'll be a big help in the future, and you'll love how solid the car feels just going down the highway.

you do those things, even before the camshaft, and i'll garauntee you'll have the hardest time keeping the thing going straight i see a 14.9 (weather and traction permitting) outta just the camshaft, and probably 14.5's or better if you pair the camshaft with a good converter and gears. though i gaurantee that if you put those two things in too, you'll be looking at getting a pair of drag radials on a spare set of wheels.

 

Wow that's awesome! I'm excited for it ! It came with 3.23 posi stock, so that's one thing down.

When I get some more money (well, a steady income), I was planning on purchasing a 700R4 out of a junk yard and rebuilding it with a b&m kit and some other goodies and installing it in my car. That way if I screw up, I can just put the old one back in until I figure out what happened with the one I build (mine is still great, but it has 123k on it). I have a good cooler with a fan and a gauge, so that should take care of the extra heat from a higher stall converter , I would think... sorry about my babbling.

Subframe connectors? I'll look into those. It all sounds great to me. I know that the passenger side strut is leaking badly too, so that may tell how the rest of them are. I'm sure that can effect my time. Thanks for the help! Also, what did you have to do to get yours to run 12s?

 

use a transgo shift kit and a decent borg warner rebuild kit, the b&m is stuff is garbage. give "fast 383" a pm and ask what he can do for a good converter for you. he works for, or manages, or owns or something, a company that builds converters and gives TGO members a really good break. i'm going to get one for my little bro's car soon. he's got a very similar goal as yours, but he's using an 89 lb9 iroc. we've had his as quick as 15.1 or so with just 3.45 gears, and a full exhaust system.

don't worry about how i got mine to run 12's. it was a carb setup and the engine worked completely differently than what you're wanting to do. i see upper 13's not being a problem with a FULL boltons, good converter, tires, and taking the time to dial in the tune.

 

Hey thanks for all the help! I didn't know that b&m wasn't all that great. Thanks for telling me. My intermediate pipe has now recently totally broken off after a bracket near the muffler, and it's totally rotted. So, I'm sure I'm losing back pressure. That's my next thing. Should I go three inch, or will that kill my back pressure too?

 

get the idea that there is a such thing as "good" back pressure out of your head completely. back pressure is always a bad thing. what you want to do is maximize your velocity control. going to a huge exhaust system is going to kill the ability to keep the velocity at a high rate. however, i've seen dyno proven gains on even a 2.8 v6 with a 3" exhaust so i don't think it'll be too big. i highly recommend the magnaflow catback. it's super high quality stainless steel, it's very mellow at idle and cruise, and SCREAMS at WOT. it's also one of the highest flowing muffler available in a catback for these cars. and it has very attractive stainless 3.5" slash cut tips.

 

Ok, that souds awesome. I'll look into it in the future. For now I think I'll just get a 3" intermediate pipe installed, as I already have an 80 series. I don't have a whole lot of funds at the moment, but I need to replace that pipe fairly soon, as it looks as if it could come loose soon. Maybe I'll try and do it myself.