at what duration does the cam sound really turn into the muscle car sound. i have a 91 and i am putting a 383 with afr 195 heads and with tpis 1 3/4 headers and removing the 2 front pre-cats and i have magnaflow catback. one cam has a duration of 236/240, one is 222/222 and the other is 228/230. i want it to be fast but i don't want someone to hear it and know its fast. which cam is the best thanks......jeff

 

The 236/240 or 228/230. But with the 383 I would go with the 236/240 . I have a 236/236 and it really depends on how loud your exhaust is and weather its a hydraulic roller cam or a solid roller. With a quieter exhaust on mine and the idle at 900rpm I dont think anyone would have a clue to how fast my car really is.

 

Also the compression of your engine has alot to do with the sound also. So does the LSA(lobe seaperation angle) on the cam. 106-108LSA lopey idle very rough, 112-114 smother idle more engine vacuum. We will need more engine specs and cam specs...

 

Lope comes from valve overlap and also depends on CID. Larger displacement can stand more overlap.

You should be ok with 228/230 duration if it has 110-112 LSA on a 383; maybe even up to 236/240 duration.

 

the one other thing i know until tomorrow is the comp. ratio will be 10.5 to 1

 

If you're asking which one would have the smoothest idle, the 222/222 would be it, assuming the lobe separation angle is the same on all three cams.

 

Yes it would. But it would also be a dog of a cam in a 383 with AFR heads....If you want to go fast the 236/240 duration cam is the way to go. Just use a quiet exhaust...

 

Jeff definitely the 228 and the 236 cams will have the more lopey idle. However more isn't necessarily better when it comes to camshafts. The more overlap the more compression you bleed off which equates to a lower dynamic compression ratio. And depending on how much you start with going with too large of a cam can render your car lazy in the bottom end.

And not to mention that the more radical the cam the more difficult the tuning will be for the EFI system. I noticed that you have a 91 car which means you have a speed density fuel strategy, this system is not near as forgiving as a MAF control strategy. Tuning with a large cam can be difficult. Also with the 236 cam you will lose some low speed manners, meaning cam surge in city driving at lower speeds. The larger 236 cam is close to that of the GM 847 cam which is a 234/242 on a 112 LSA. I can tell you that the 847 cam has a noticable amount of cam surge even in a LT1 MAF car. My suggestion is a cam around 224/230 on a 112 which will offer better drivability than the larger cam.

 

We were able to tune all of the cam surge out of my car(91 speed density) and my cam has a 110lsa. But in the begining before the fine tuning, it was there. It really depends on what you want and what you can live with and how fast you want to go. I agree that the 224/230 on a 112 will be a better driver. Right now I am looking at going to a 254/260@50 on a 112lsa, but mine is not a daily driver and I can live with all the little quarks of a big cam.

 

I agree it can be done. He just needs to find a competent tuner with a good load bearing dyno. With that tool a good tuner can do a good job tuning it in. It just takes a bit of time to get a good tune on a SD strategy car.

 

Yeah, it took us 3 different nights and a total of 26dyno runs to get it perfect. I dont think the tunnelram helped much either....Well of those 26 runs, 10 or so were us just playing with timing curves and fuel mixtures to see if we could squeeze any more HP out of it.

 

I'm using a 219@.050 single pattern in a 383, trust me it's no dog. see sig.