SSV8

I'm looking to get used prc stage 2.5 5.3 heads and ms3 cam used, would the pistons require flycutting for this combo? Can't seem to get an accurate answer. I did read if the ms3 wasn't spec'd for the 5.3 then it would need fly cutting, but how would I know if it was spec'd for the heads? I've read so many answers I don't know which is right. I emailed Texas speed, but they haven't gotten back to me. Could I go with a different cam with the 2.5 5.3 heads that wouldn't require flycutting if so which cam would be best suited for these heads? Would prefer the ms3 though since I can get it used at a good price and people seem to love it with these heads.

07NBSChevy

iTrader: (1)

What engine will these be on, 5.3? If larger than a 5.3, ignore most of what I said below.

If a 5.3, due to the larger valves with the Stage 2.5 Heads (2.02" Intake/1.575" Exhaust) in a 5.3 Bore 3.78", anything over a 224/224 .580/.580, or around there, generally need the pistons flycut. There may even be some negative affects of the larger valves used in a small bore as well.

The MS3 cam is a Max Effort cam generally used in LS1/6 engines, even some 6.0's. It is going to be a huge cam in a 5.3 and be a dog under 3500 rpm. I would Flycut the pistons or get pistons with valve reliefs.

Will this engine be used in drag racing? If this is a daily I would look more into a 220/224 or 224/224 up to cam.

Others will chime in who are more knowledgeable on this and may recommend you something.

SSV8

This is for an ls1. Car will be a street car and see some canyons as well. Probably take it to the track 4 or 5 times a year just for fun. I would like to get the torque in the 400s though.

07NBSChevy

iTrader: (1)

Ok, check out this thread. This is a build from Jason (at Texas Speed) LS1 with Stage 2.5 5.3 heads, MS3 Cam, as well as dyno results. Made some good numbers as well.
https://ls1tech.com/forums/dynamomet...o-results.html

Should answer all your questions, no flycutting.

HCI2000SS

iTrader: (2)

I run a cam almost identical to the MS3 and I run the PRC 5.3 heads but on a 6.0 not a 5.7. Are you a manual or auto?

Aaron at SDPC

There should be a serial number hand engraved on the PRC 5.3 heads. Give TSP a call with the number and they can reference the original build sheet to tell you exactly what those cylinder heads were setup for.

Bspeck82

I dont forsee 400 tq with those heads. Maybe with afr 205s. The 220 224 cam will be great for canyons, should make torque everywhere and doesnt need much converter to run right. The streetsweeper TQ by Ed Curtis will make more power then the comp.

Bspeck82

Eps has a good 222 226 as well. Or a voodoo 222 228

farmington

iTrader: (14)

canyon/road racers need bottom end torque. go with a smaller cam. 224 sounds about right

Bspeck82

indeed. I wouldnt go any bigger, you don't want to have to wind it up to 4500 to make power over a canyon. I know lots of people who usethe eps cam for circuit track and they love it. Make sure you build suspension too.

tech@WS6store

iTrader: (2)

Not just tq is needed but also a stable marine style lobe as well. You can just throw some catchy name cam at a setup like that and be optimized. I would use the HUC lobes as they are higher lift marine style stable lobe that work well with any valve and are made for sustained rpm esp mid range. They make great power and are a better design than alot lf the similar @.050 cams and lobes out there.
The ms3 isnt max effort although it is considered close, its more of a peaky higher rpm cam that like most said will sacrifice the power where youd want it.
Id recommend a 223/231 on huc lobes in the 113+2 lsa/icl area , run a dual spring and an 11/32nd manton pushrod and be done with it. most people will recommend a ti retainer, but you can use either honestly ti or tool steel.

SSV8

My cars a manual. How would a 223/231 cam fair in roll racing. I forgot to add I do a lot of roll racing. If I go with a smaller cam like this then I wouldn't need any fly cutting correct?

tech@WS6store

iTrader: (2)

No fly cutting.
A smaller cam like that wouldnt fare too well in roll racing, maybe some more exh duration and a 227 intake dur and prob a 235 exhaust which is a"normal stage "x" cam" spec just on lobes designed for sustained rpm for road racing. add some 390s or 410s and you would have a better time on the roll races. Its not going to pull super high with an ls6 intake maybe 6300 or so, a fast 92 or 102 would add about 100 to 300 rpm to that prob. thats as big as i would go though.

That would still be a good road race cam but have a better time roll racing with a manual and youd see quite a bit of power on say 100shot of nitrous also.

Bspeck82

You cant build a car that excels from a dig, canyons and from a roll. Since its a street car build it as a street car and just enjoy it. I'd get a cam with a nice flat torque curve with stable lobes like Ws6 said and a good set of heads to match.

SSV8

I'm aiming at building a car that does ok in everything rather then excel at one thing. I think I'm going to call a couple vendors and look for something with a flat torque curve like you said. What do you guys think between prc 2.5 5.3 heads compared to livernois stage 2 243s?

Bspeck82

Depends on the budget. Lots of people run the prc heads as well as tricks heads and they like them. AFR heads make massive power as well, provided your wililimg to pay. If you want a very smooth running reliable engine the PRC heads and an Eps 222/226 cam (or similar from a reputable company) will be great. It will make smooth power throughout the entire rpm range and in any gear. Speaking of which it wont need a lot of gear to move, which is good for freeway cruising with a nice exhaust setup that wont drone your ears off. You wont need to worry about constantly shifting gears to move in the canyons. Great combo for an everyday hot rod on 91 pump. AFR heads may need aftermarket rockers, I dont believe PRC does, so consider that as well.

SSV8

well I'm looking to get used heads and the prc and livernois stage 2 243s are about the same price which is why I brought it up. I've read tons of good info on the prc, but not as much info on livernois, though I did read some and it seems the livernoise heads seem to bring out a little more power then the prc heads. I will look into that eps cam. I like the fact that it won't drone as well since I am already going deaf. I've also read the tr224 is a real good street cam with a linear power band, any thoughts on this cam? Would a cam that has some lope to it drown out my ears? I wanted a little lope, but I don't want to deal with the drone when taking 8 hour rides.

Bspeck82

Loud exhaust will make it drone, not so much the cam. I recommend the magnaflow muffler for a nice quiet ride that makes noise under throttle, but can hardly be heard while cruising. TR224 isnt made anymore, I believe thunder racing went belly up. Anyone can grind you a cam like that, single pattern cams usually make more torque under peak torque, but less power past peak torque. I believe a lot of new circle track guys use those kinds of cams for a very flat power band thats easy to predict. For a street car with full exhaust and a muffler, for sake of efficiency and smooth running operation a little bit of duration split is perhaps optimal. 222/226 and 222/228 would be great for a smooth powerband that doesnt waste time makimg power above whats comfortable on the stock bottom end. Should be very predictable and it will have a slight lope at idle, nothing crazy. Wont draw unnecessary attention, but will turn heads when you fire it up in a parking lot. As far as heads go, don't fall into the peak flow trap, its mid lift that matters. Think about it, you reach midlift twice throughout the cycle, the valve goes up and down and that isnt all! There is so much to head design beyond peak airflow. I'm sure both will do fine, if your on a budget the livernoise for a grand will be a great buy, ive seen PRC heads with mild cams run mid and low 11s in the quarter. Thats not bad for 20 year old tech with 346 cubes NA in a grocery getter. I believe PRC heads are like 1600 with springs. If you got ls6 heads then you could port and polish those with some milling and a valve job for around a grand plus shipping. Thats up to you. I wouldnt bother with working on 241 heads.

tech@WS6store

iTrader: (2)

Well livernois are about $5 more than our tfs 220 fast as cast heads. which have PLENTY of room to grow.

Bspeck82

OP should call and talk about building a package from you guys, heads cam and all the necesseary accessories....of course I would call multiple vendors like Brian tooley racing, Texas speed etc etc. See who will give you a better deal.