-I have an 88 iroc-z. Putting in the new motor this week and im just getting antzy about what it will run. Motor is a 350 - .040 over with Eagle 3.75 crank. Eagle flat top pistons and Eagle 5.7 rods. Patriot aluminum 190cc heads, Comp Cam 253/253 duration .525/.525 lift, Edelbrock air-gap rpm intake and a holley 770 carb. Got headers and a basic aftermarket stock exhaust. Trans is the stock 700r4. Has a 4.10 gear with a shift kit. Im running dot MT 10.5s on it. Suspension and body is all stock. Getting antzy cause im really just looking to run better than my couzins Vette (which ran 13.5 today). Computer programs have said 12.20s while a buddy of mine said with the aluminum heads it could go into the 11's. Just looking for different inputs and honesty from people with experence would be great. Thanks to those who reply.

 

its going to be kind of hard for 11's. Are you running the stock converter? The heads are kind of small. The big problem is going to be hooking up. With no mods to the rear suspension like (LCA, LCARBS and most important SFC) It might even be hard to go in the lows 12's. But for sure you will get lower than 13.50. I think you have a low 13 to high 12 second car

 

My combo and times are in my sig. With it tuned and some traction you should be in the 12's with no problem.

How much does the car weigh and what torque converter are you running?

 

I'm betting on mid 13's till you get the rest of the combo matched with the engine. That means, changing the exhaust, converter, suspension work, tuning the engine...

 

-i think im going to get spohn SFC's and im not sure about torque converter yet. Any suggestions?

 

Assuming a proper convertor 11's should be easy with a combo like that. At absolute worst low 12's.

 

not with a stock exhaust and no suspension mods, its going to be to tough to do all that. Take it to the track and let us all know what you run

 

SFC will be nice, but I would get LCARB's and a new converter first. You need a converter that will put you into your power range. Depends on the specs of the cam, gearing, weight of the car.

But yeah, with tuning, traction, and the right converter, you should be in the low 12's if not in the 11's. All depends on your tuning abilities and if you can get the power to the ground.

Run it and see what it does.

 

-Yea i finally got out to the track this past weekend. I wasn't expecting much considering the stock trans and converter. The first pass i short shifted it and took it easy to 14.59. After that i went back and checked a few things just so the next pass i knew i could at least get on it a little bit. I bumped the timing to 25 degrees.

The second pass it came out like a dog considering the cam doesn't kick in until 3 grand (which i know is too big) When the shift light came on at 6 grand in second, i shifted it, and then watched the tach go to about 7200 before i caught third. I started laughing in my helmet and let off a early.

Came around and got my slip -- 14.12. Then the car died out and didn't wanna start. Got towed back by golf cart to pit area and found that the car had flooded real bad. I got it started after messing with the carb a bit. I just put it back on the "just in case" trailer (glad i brought it) and figured no sense hurting my motor. All in all i still had a little fun.

After getting back to the shop, i found an old (non-used!) b&m racing trans for an 80 something firebird. So that and a new converter is where i'm headed next.

 

It's always nice to get a baseline even if it's bad. At least you'll know what any changes can do.

The first year I raced my car, I took it to the track as I bought it except I first installed SFC and gutted most of the interior. The first pass was only a 15.0. By the end of the day I had it down to 14.2. By the end of the season, it was 14.0. Not great but it was still just a gutted out street car running on ET Street tires.

After the first season, the 700R4 tranny got yanked out and a TH350 with a 3800 stall converter to match the cam that was already in the engine. The smogger heads were yanked off and a set of large valve, ported out camel heads were installed.

First pass of the second season, it ran 12.0. Everyone was asking where I hid the NOS bottle. Some better heads and a different tranny with a better converter was worth 2 full seconds.

That was 10 years ago. The car has come a long way since then.

 

-thanks to all of you for the input. Now down to business


-The trans i actually found was a B&M th 350 but it has a torque master 2000 converter. I think im going to switch it out for a torque master 3000 because that puts me directly in my power range and also because the warehouse i deal with can get it for like 230 bucks brand new.

-Im hoping to get this in by sept 26 because thats the next race at Route 66 Raceway (which is my local track and by the way is just a fantastic place to race if you ever get the chance)
-Anyway i'll definitely write again with the progress. Thanks again

 

I'd go even looser on the converter with that duration on the cam. This is just a weekend car right? or is it a daily? With the 248/248 @ .050 of my old cam with the same lift as yours, I was recommended a 4,000 stall. The looser converter did pick up over the old 3,500 stall. My new cam has 255/265 @ .050 but haven't taken it to the track yet, that'll come this Saturday. Probably end up running 12.20's lol.

 

Wow its been a long time since i posted here. I just went out yesterday and ran true street at the nmca/nmra super bowl. I ended up with an average of 13.09, but didn't win the 13.00 index. The best i could coax out of the car to date was a 12.84. I put 4.56 gears in, but street driving is a little tough. (2750rpms when cruising) I put an msd 6al in the car, and an msd distributor. The only real problem i have is when i'm in the burnout box it sounds like the car is hitting a rev limiter, but it isn't. It sounds like there's a bunch of rocks in the exhaust. Any ideas?

 

What converter did you end up running?

Do you have any rev limiter? What RPMs are you running up to during your burn-out?

I have no love for vacuum secondary carbs on a race car (that isn't being run in a tire-limited class, anyway). With a proper converter - and even 2000 stall is sufficient on a 350 - you can easily run a 750 double pumper.

What exactly is your "basic aftermarket stock exhaust"? I'm running a single 3" cat-back in both of my LS1 Camaros, and they aren't being hurt by the exhaust. But, a 2.5" or 2.75" cat-back would restrict your combo.

 

"sounds like it is hitting a rev limiter"...I would be thinking valve float or detonation. Patriot sells some good valve springs, but I don't think they use them on their cylinder heads. What compression ratio? What fuel? I think your combo is good for some low 12's or high 11's, but the heads may need some port work and you will need a 4000 stall converter. I also agree with five7kid...dump the vacuum secondary and throw a 750 double pumper on there.

 

The rev limiter is set at 8 grand, but i don't have a two step for the burnout. When im doing a burnout the rpms don't get much higher than 5500. I mean its not just when im in the burnout box. Even when the cars just idling in the driveway in park and i start to bring the rpms up, this same noise begins to happen. I have a 750 double pumper carb on it. I think i may have something wrong in the ignition. I got a pro billet distributor from a friend who used to run it in a top sportsman car.

I have trick flow headers on the car, but the rest of the exhaust is basically stock. The stock muffers rotted a couple of years back, and i just had a local muffler shop throw something standard on it.

I have a 3200 stall convertor in it now.

When i bought the bottom end from eagle they said it was an 11.1:1 cr with 64cc heads. I called patriot and they said i could get the 185cc heads with 72cc chambers so that was what i did thinking the lower cr would help with street driving. I'm thinking the cr is around 9.4 or 9.6:1 now.

I usually run the car with rockett brand 100 octane fuel.

Im not sure if the ignition is giving me a big problem, or these parts just don't work that well together. I bought most of the parts when i was 18 thinking i knew everything there was to know. Now looking back i know i should have taken a little more time.

 

aluminum heads with that big cam should love 11 to 1 compression. It could use a single plane intake and a good carb. Alot more stall and it should go 11's. I dont know what springs you have but could be valve float problems too.

8K limit is WAY to high. No more than 7K on that motor til you figure out whats going on with it. That cam should peak in the mid 6000 range and hold onto 7K if the heads are good enough. Sounds like it may need better tuning and possibly some better springs to control the lifters.

Question tho, is that a solid lifter cam or hydraulic lifter cam?

 

Is it this cam? 12-214-4 305H Magnum Hydraulic flat tappet. Throw a set of springs at it. Mine would run into a wall and sound like total crap with weak valve springs, popped some 987 springs in and was much better. Does it always happen at 5500 rpm? What happens if you slowly come up on it?

 

That is a HUGE camshaft for a 9:1 350. What is your timing setup? Any way you can get some more compression in the motor? Have you ever tried advancing the camshaft? Ditch the 3200 stall converter and step up to something in the 4400 range.

I had a camshaft similar to that in an 11:1 406 and it was really choppy! I ran 12.2 at 110mph using only 2 gears in my TH350 (3.73 gears when I really needed at least a 4.56). LOL

 

The cam is a hydraulic flat tappet and yes its the 305h cam. Even when i bring the r's up slow at around 3800 the noise starts to kick in.

I looked up the specs on my current springs, and this is the spread. EvilC, was the difference between your springs about the same, or was there a bigger difference?
Current:
Spring Pressure Closed: 115 lbs. @ 1.800"
Spring Pressure Open: 310 lbs. @ 1.225"

987s:
SPC: 121 @ 1.800"
SPO: 343 @ 1.200"


I think im going to play with the ignition a little more. Right now the initial spark is set at 17.

Or i might try to get a hold of some used 64cc heads and see how much a difference there will be by bumping the compression.

I keep thinking that the patriot heads are just lighter stock heads. And then with a low compression number and a big hyd. flt. tpt. that this might just be the way the car is going to run.

 

If those patriot heads are 64cc chambers its already at 11 to 1. its a 383 motor not a 350. 11 to 1 is good enough for that cam, something else is causing the problems and I would look at fueling and timing. Springs seem abit weak and could be floating the valves. Thats a good bit of cam for a 383 and those heads. I'd like to see 10 deg less duration. Definately needs more like 4000-4200 stall speed.

 

I'm not sure what my stock AFR springs were rated at but it wasn't enough. It started breaking up around 6200 and now it does it just a bit past 7000 it seems like. This was after switching to a hydraulic roller setup from a solid flat tappet. Even with the lower compression, that engine should pull higher than what it is.

 

evilcartman what AFR heads do you have? are they the AFR eliminators ones with the beehive springs? Also what is the size of your cam? Just wondering because I have quite a large cam in my 350 with the AFR 195 eliminators and havent had any problems yet but I havent shifted it past 6000 yet. Thanks for the info.

 

They're the older AFR 195 heads from 8 years ago, non beehive. The stock springs that came with it worked ok with my old comp cams 294S solid lifter cam. It had .525/.525 lift and 248/248 duration at .050. Took it up to 7500 a hand full of times screwing around but mostly kept it around 7000-7200. Switched to a custom grind from an LT1 hydraulic roller setup and it's 4xx/4xx lift but 255/265 duration. 1/4 mile times were about the same as the old solid lifter cam but I had to shift a little earlier. It doesn't like going much above 7k now but it's better than floating the valves at just 6200.