I'm slowly piecing together a H/C/I build on my 2002 sbe 346 M6 Trans Am stock 10-bolt and 3.42 gears and one of the last pieces I'm still undecided on is which cam I am going to run. After posting before about going with the z06 lightweight valves and 243s or the PRC 225s, I sold off those valves and heads and am going with the PRC heads.

My goals are a very streetable/torquey 450+rwhp/400+ tq car that won't see track time any time soon. I have 93 octane available close by so am wanting to run mid to high 11s in compression. This is not my daily driver so when I drive it, I have fun and routinely like to spin the engine to mid 6 grand even on the street. I will be running stock size Sport Comp-2 BFGs for now. Since I am buying the heads from Texas Speed, I am going with their dual spring package with titanium retainers. I was also going to go with either the torquer V2 or V4 cam in the package as well, but am not sure if that would be the way to go or not for my goals in terms of combined drive-ability and power. I know something like the SSHT or SNS 2 cams might be better but wanted to solicit opinions based on the parts I'm using below on my build.

Here is the stuff I am going with on this build:
PRC as cast 225 62cc heads with hollow stem intake valves and either .051 GM MLS or Fel Pro .041 head gaskets
FAST 90 intake and WARR 92mm TB - already purchased and near breaking even after selling off my LS6 intake and stock tb
Powerbond 25% ud pulley
SE 1 7/8 headers to FM Merge dual 3" to single 4" to possibly 4" e-cutout and back to 3" LM1 currently on car (wanting to replace with something quieter as I'm sure this is going to be stupid loud)
42# injectors
TBD new clutch
Stock rockers with trunion upgrade
LS7 or Morel drop in lifters
LS2 timing chain
Melling standard replacement oil pump M295

That's everything I can think of for now.

 

I'd have Tsp cut me this: 232/240 .629 .615 113+2

if that was my car .

 

Thanks for the recommendation. What would the overlap be on that? I'm not sure how to calculate with advance in the cam. 10 degrees? Also, will TSP add any fee to custom grind in the package deal with the heads/pushrods do you know?

 

2 tips....

1) with really good flowing heads, there is no need to overcam this. A large cam is a bandaid in my opinion for less flow from the head.... one reason why square port and rectangular heads have a lot more exhaust duration than intake. So once you have flow, all a big cam is goona do is raise the Powerband while losing low end. This is a street car, coming from experience, you will want low end torque. Especially since you are stock bottom end, I'm assuming you want to shift around 6750-6900? That is peak on a larger cam. I had a 236/238 cam on stock heads, felt great. Seemed like it was a good cam only car. Then I put on heavily ported 227cc 799 heads, and while I gained a little down low, It felt like a turbo kicked in around 4700 rpms. It shouldn't have felt like that, too much cam, too little low speed air flow, I knew the cam was too much now. I would recommend for you no more than 232 intake duration. I'm not a cam guru, so I'll leave it at that. I could have ran a 230/236, gained about 15 tq in the midrange while losing 5hp if that up top. I also wouldn't have that soft spot from 2000 to 4000.

2) ditch the Powerband. The more advanced reads I have seen are that underdriving the accessories really doesn't help much. Unsure if the weight is lighter than stock. I contacted ATI about needing a balancer for my 427 build. The guy I spoke to said that the accessories have become way more efficient than back in the day, and while there are gains to be made, it's not much and the water pump is the biggest drag. So if u did electric, the Power loss from the other accessories will be minimal. The biggest thing he said was the ls stuff needs a heavy balancer to help dampen, and they actually gained 8hp by replacing a lighter pulley with a stock sized pulley and actually it was heavier than stock I believe. The gains he told me were from the better harmonic dampening, which better dampening means your motor will last longer. So he sold me the heavy pulley. May not rev as fast and sound as cool, but will make more power and last longer. Those are a few of my goals.

I usually post too long and people stop reading but hopefully u read it and decide what's best for u

 

I appreciate the input and I hear you on the over-camming. I definitely wouldn't mind sacrificing top end for low to midrange power. That's an interesting point in regards to using the stock balancer over the underdriven one. So the stock should be better than even the 10% ATI you think? I've heard of the 25% pulley gaining around 5-7rwhp and was trying to use that in attempt to get to my goal of around 450rwhp or more, but if it's going to take away power I'm all for selling it and gaining back another $140.

 

10 degrees

intake duration + exhaust duration ÷ 2
Lsa x 2

duration - Lsa = overlap

 

Go with the summit udp

 

the guy I spoke to said a heavier pulley is always recommended by him on ls motors, especially larger cube motors. It isn't as important on the smaller cube but still recommended. People seem to forget why the balancer is even there in the first place..... to balance. How do dampen things? With weight. I didn't no much before talking to him but it makes a,lot of sense. A good balance is needed, and I would prefer to spend a few extra dollars to buy one from a company who I'm sure has invested hundreds of thousands in R&D. The lighter pulley may gain, you are right, but a heavier pulley I am told will gain more by reducing harmonics. Nobody has any personal evidence because nobody puts a heavy one on to prove a point. People want that satisfaction of knowing their lighter pulley not only sounds cool but makes more power.

 

Thanks.

I will have to weigh them since I have both the stock and the PB balancers, but I could swear the smaller one is just as heavy as the stock. I did just read that the 10% ATI does free up slightly more hp than the 25% which would support your information due to it's superior dampening. I will probably weight those this weekend to see the difference just because I'm curious now.

 

Interested in the weights, my ati is right around 8.5

one thing to keep in mind tho is where the weight on the balancer is. More centralized will be easier to turn vs weight towards the outer shell which is harder for the motor to turn this helping harmonics I believe. So one could say o 10% underdriv, same weight as stock, best of both worlds. Wrong. The larger pulley with same weight will still have more leverage and thus I believe will control harmonics as well.

All these companies selling underdrive bragging about freeing up horsepower and spinning quicker......but do any of them brag about reducing engine harmonics vs a stock balancer?

 

Texas Speed will be more than glad to help you spec out a good cam to fit their heads and your combo. They grind the cams on premises and nothing is farmed out. Quality is second to none..

 

FWIW my ATI 10% UDP is ~8lbs compared to ~10 lbs stock. You can always call them and see if they have any "scratch and dent" blemished ones. I got mine for $212 back in 2013ish. They used to have them on ebay but I got mine just from calling them. The "blemish" is that the timing marks are not correct or something, but that didn't matter to me.

If you want mid-high 11's for the CR you might want smaller than 62 cc chambers, and/or thinner head gaskets. Looks like WS6store is making some .45 gaskets, I wish they had those when I did my build.

Also some little thing to consider are trunnion upgrade for the rockers, going for 11/32 pushrods (looks like summit has some now vs the spendy Mantons), ARP head bolts and balancer bolts, new cam retainer plate, new lifter trays, and an 85mm MAF or SD and larger lid to match that FAST you picked up.

I like the 3-4" y-pipe, wish I would have done that too.

For injectors, if you happen to find a deal on some I wouldn't hesitate to go down to 39# unless you plan to spray it in the future.

I know this is a cam thread, if you wait till spring you are welcome to ride in mine and see what you think (226/230-113+2). You already know my thoughts on it, but this is my only cammed car so I can't compare it to others.

 

i also have a the 3-4 inch y merge/dump. duals, long story but not ideal for my setup. one cool thing about the single pipe, is that i need a rear exit to pass inspection. so the shop made up this custom pipe, i remove the turndown after my muffler, and clamp on this 2.5" 2 piece pipe that runs over the axle. after i pass inspection, off comes the pipe, on comes the turndown.

 

I'm really considering ditching the pb pulley now. I will look out for a blem ati 10% and if not just run the stock balance. I already got some 42# gtp injectors ready to go and will be doing the trunion bushing upgrade for the stock rockers. I am looking into the 11/32 prs just need to make sure they will fit in the prc 225s.
For compression I think they only make those heads in 62 and 68cc chambers so will probably have to go with the .041 gaskets. I also have a arp 12 point head balancer bolt ready to go and was planning on the ls2 trays as well.
I will look into a bigger lid and maf. What sizes would you suggest on those? 104 and 85? Unless Carl thinks I should go SD. I would definitely like to see your cammed cars manners this spring.

 

I have a pretty similar set up with a few changes. I have stock 243s, just a spring swap to BTR .660 springs with Ti Retainers, a 92mm Fast, SE True Duals and a high volume oil pump.

Other than that, i made 428/375 threw a 60e with a yank SS4000 with a SSHT cam.

 

How come the merge didn't work out?
what size headers are you running?

 

the merge does work out, after the muffler i put a piece of pipe that goes out that back to pass inspection, then take it off after i pass. the arp balancer bolt isn't necessary but if you already have it you have it. stock bolt is 5 bucks vs arp at 20. not like head bolts where 1 change and you are breaking even on bolt pricing.....how many times are you planning on pulling your balancer lol

 

Ok got you. Misread your post on the merge. Yeah already have the arp bolt. Not sure lol. Doesn't hurt for the money though. I'm still undecided on exhaust after the merge. I want to maximize flow without screwing with low end torque using the y pipe setup.

 

just dump that ****....the drone does get annoying at times but haven't tried other mufflers and was told the dynomax bullet has a lot of drone, but man it screams when you are on it lol

 

Same as listed, SE 1 7/8th