Insane1

How much will I gain/loose on my 383 L98 motor between a 185cc and a 200cc runner head? The intake/runners/plenum have been partially siamesed and ported.

I am looking at a set of aluminum heads that have a runner of 200cc. They also come in straight or angle plug design. Which is better and which ones would work with stock exhaust?

I am planning on about 10:1 compression, roller cam (any suggestions?) and 52mm TB. This is for an 85 with 4+3 tranny.

JackDidley

If the 85 came with straight plugs stay with them. AFR makes L98 angles but most other aftermarkets have the plug at a different angle.
On port size, 185s will likely flow closer to what the intake will handle.

Insane1

Even with the mods to the intake system that I have? I also have a gutted MAF and K&N with a cut lid.

I am also running 30# injectors.

Would the 200cc runners hurt power that much?

vader86

If this is TPI, then 185cc is optimum. Intake cant flow enough to warrant using 200's. 200s arent going to hurt anything, but you'd notice a difference on the low-end between 185 and 200 if you tried both.

If you get an angled head, make sure its 'L98 angle' and not a proprietary angled plug. Otherwise get straight plugs.

If youre switching the 85 from tappet to roller, then something like the Accel 211 or TPiS ZZ9 would be as small as I go, slightly bigger would do well but not over 220/220 with TPI on it because you wouldnt get what the cam can do.

Insane1

What effects would 170cc runners have? I am thinking of getting the LPE 74211 cam. That is the same as the Accel one correct? I am looking for bottom end grunt on my motor.

Thanks for the replies everyone. My motor is coming apart tomorrow and I am going to check on a couple things and then start getting the parts. I am looking at the Edelbrock Performer heads. $1000 a pair. Between those heads and the cam I am about to my budget for this.

vader86

Smaller ports on the heads tends to lower the rpm where the peak port velocity occurs, which improves the torque and limits the high rpm HP.

Accel=LPE, yes.

CorvAdel

I am no expert, but I can tell you this...I was looking for low to mid-range grunt when I was building my motor. It is an 87 with stock heads, etc, but all ported. I picked the LPE211 after asking the question here, and I have no regrets at all.....my engine with A4 and 3.07's loves the cam..very responsive and pulls great right up to 5000....then the power tapers off even though it will make just over 6000.
My only other tip would be, if possible, get your chip tuned using a dyno...I went with a mail order tune, and even though it is good, there is a burst of ping when nailed over 2500...
Good luck with your project.

Insane1

Thanks! That's what I want to hear. I don't want it in the upper range. I want it from cruising speed up. I am beginning to think I might have at least this motor figured out.

88BlackZ-51

so you are going with the stock intake on a 383?

Insane1

Yes, reworked but stock.

88BlackZ-51

and do you have any power goals?

88BlackZ-51

do you know what the hp/tq peaks at?

JackDidley

Now that you have selected parts, find someone that can tune the chip so it will pass emissions, and drive nice. If you have a local person it can save a lot of time and stress.

Insane1

Alvin has done the tune that I currently have on my motor.

I am trying to get 300 rwhp. I am at 245 now with the 76cc heads. Would the LPE 74211 or the LPE 74216 cam be better? I believe the duration @ 0.050 on the 74211 is 211/219 and the 74216 is 213/219. Lift on the 211 is 0.530"/0.560" and the 216 is 0.493"/0.503". The heads say they will handle up to 0.560" lift. I want the peak hp and tq low in the rpm band. I think the 211 cam will work in the 1000-5000 range. I will be putting a MSD 6AL on it also and probably put a 5000-5500 limiter chip in it. It comes with a 6000. Maybe I will just use that one.

vader86

You should be able to get your goal with either cam, but you dont really need the MSD box. Intake wont let you overrev this motor anyway.

Insane1

Father-in-law bought me the MSD box. He saw an article about it making more horsepower so he bought one. I tried to tell him it wouldn't neccessarilly make more hp on this motor but he takes what he reads in the mags as gospel and I can't get him to think anything different. Easier to let him go with somethings as long as they don't hurt the motor then to argue with him about it. He was sure that the 52mm TB was gonna increase the hp. After I had my 48mm rebuilt to 52mm and dyno'd with 5 les hp and 17 less tq he still didn't believe it wouldn't help.

vettes

I have this cam lpe74216
213/219 , installed,but have yet to get programed chip.Dont know where to get this done.

Pete K

Don't eliminate the edelbrocks from your list of possibles. I swapped a mild ported set on my 383. I went 116.50 mph in the 1/4 first time out(with stock tuning). The runners are now at 175 cc due to the small port work. I bought them because they were cheap and was pleasantly suprised. Not the greatest head, but decent.

cv67

I wouldnt go any bigger than 185. Should be a real torquey motor!
Port that TPI base and get some aftermarket runners if you can. Those two cams will be very close in performance IMO.