I'm in the process of building a parts list to buy for some increased N/A power to my LS6 in my '01 C5 Z06. I've done quite a lot of research but the more I learn the more I realise I have no idea what would be my best option. My goals are lots of lope/chop so an aggressive cam and as much area under the power curve as possible without going too mild on the cam.

I've already got some unknown brand long tube headers, an X-pipe and a borla exhaust

For the cylinder heads I'm thinking AFR 215cc mongoose heads, I would go with some 243's worked by AI or TEA but I'm in New Zealand so shipping and wait time make that option less attractive. My concern with the AFR 215cc heads is whether I'd have to fly cut the pistons and whether there's better heads for my aggressive cam choice, any suggestions appreciated Also I have no idea how to choose valve size (LS3?), if I need trunnion rockers and what spring size and hardness but figure I could phone them up and they'd point me in the right direction

For my cam I'm thinking of going with a BTR stage 3, it seems to be the most popular so must be a decent cam, any other better alternatives that would pair better with the heads?

I've heard the factory LS6 intake is decent but will get a FAST 92 intake if that will add more area under the curve, I've heard the FAST 102 intake isn't worth it unless the rev limit is significantly increased.

For an air intake I'll get Vararam which seems to be pretty popular and has some good reviews

Would an LS2 90mm throttle body make a difference?

Put an underdrive pulley on

I'm probably going to get it tuned to 95 octane but do have 98 octane readily available if that's going to be worth it for the extra advanced timing?

With the aggressive cam I'll likely go with 4.10 gears down the track

Open to any advice and really appreciate any input you guys may have I've been lurking on a here a while and am very impressed at some of the unique set ups and results on your rides, from the drag strip to the track to the show room floor!

 

I have the TSP stage 2.5 5.3 heads a BTR stage 3 with a Fast 92. 453/402 to the wheels.
the cam idles great and isn’t bad in traffic. The gear will help. I have a stock 3:42 in now but a 3:90 sitting on the shelf I need to install.
My buddy had the same setup with the AFR heads and made about the same power. I think you have a good plan.

 

The FAST 102 often requires shorter engine mounts or firewall mods to clear. A 102mm TB can also be harder to tune and provide less progressive throttle control on a 5.7.

Overall a good parts list. I like 3.73s on a street car, canyon car or track time, short enough for a nice advantage but wide enough not to be shifting overly often. If you are not running a drag oriented sticky tire I don't see the lower gear (higher #) adding performance. IMO

AFR and Trick Flow both make great heads. The Callaway Honker and Vararam are both good air intakes. Is the FAST worth it over a LS6? All depends on budget and goals, from the feeling I get in your post, it is.

If 95 octane is readily available you might want to call /email a cam designeer such as Cam Motion, Tick, EPS cams, etc. You may consider running more compression, and maybe more advance in the cam. I've fly cut pistons it does make you a bit nervous but wasn't a big deal. I would search out a core LS1 head you don't care about to do it, any cathedral port style should work..Search LS1tech forums as well, the more you read the more you read the better.

IMO past 228 on the intake gets harder to tune out idle surge and overall smoothness driving around town. I'm on a CamMotion 232/236 112+2 with some old WCCH Edelbrock heads and a friend and I tuned the car together. He is on a CamMotion Titan 4 228/231 (?) with AFR 205s, and FAST 92. The AFR titan 4 combo has been a fast reliable combo for track time. The AFR combo did require a fly cut, chambers were ~59cc, my motor did not require a fly cut likely due to less advance in the cam. I'm also ~59cc chambers.

I'd run a Morel or Johnson (not Johnson hylift) lifter, 11/32 push rods or 3/8 diameter if they clear the hole in the head. A carbide gasket scraper helps clean up the deck of the block. Always measure pushrods and pistons to valve clearance. I'd also replace the lifter trays with new GM units, I would not trust any other brand.

 

Thanks for your response I'm all ears
Are your TSP stage 2.5 5.3 heads, 243 heads that you've sent to Texas speed to get CNC porting done or can you buy them off the shelf sort of thing? That's some impressive power to the wheels I'd be more than content with those kind of numbers! Did you keep your factory throttle body to pair with the Fast 92 intake? Glad to hear that the BTR stage 3 behaves well round town hopefully my tuner can get similar drivability to you. Did you have to fly cut your pistons for your heads cam combo?

 

Thank you very much for your well thought out and informative response

The FAST 102 sounds like too much extra work especially to end up with less progressive throttle control.

I guess I was mainly thinking 4.10 gears cause if I'm going to swap the gears out I might as well make it count but you're right I don't really want to be rowing through the gears constantly and 3.73 sounds like the the sweet spot.

Just looking at the Callaway Honker now and it looks easier to install and like there would be less chance of hydro locking the engine from running through a deeper than expected puddle in comparison to the Vararam with it's low intake ducts.

Same thinking the FAST intake will be worth it, budget wise I'm thinking spent it all now so I don't have to keep going back for retunes.

95 octane is readily available and even 98 octane is a short drive away. So I'll definitely look at getting a custom grind cam. I'm not quite confident enough to do the heads and Cam myself so will be taking to my mechanic who is confident working on the car but not sure if he will have the tools to fly cut the pistons. Would the 243 heads that are on there be able to used or do they have to be 241's to have enough room for the tool? I like the idea of upping the compression however that would increase the likelihood of needing to fly cut the pistons and the same with advancing the timing.

Sounds like your friend with the AFR 205's hasn't had any trouble with weakening his pistons from fly cutting them (some threads say that it's an issue with LS1/LS6's), I'm surprised he had to get them fly cut with only running a seemingly not overly aggressive cam

Your CamMotion 232/236 112+2 sounds like an aggressive enough Cam for my liking what kind of power did you end up putting down with the WCCH Edelbrock heads?

Thanks for the advice I'll have to do some research on whether they'd fit the heads I end up going with, I'll be sure to get my mechanic to measure the piston to valve clearance before he bolts it all back together. Cool good to know I'll replace the lifter trays with new GM units to be safe

 

My 232/236 is a 112+2, .612/.612 Johnson 2110s, Edelbrock West Coast Cylinder Heads ported to 215s. FAST92 / LS2 tb, Stock diameter ATI balancer, LG 1 3/4" pros 465rwhp /425 twtq STD corrected.

Titan 4, AFR 205s, Morel drop in lifters, FAST92 / LS2 TB, Kooks 1.75" headers, ATI 10% under drive balancer 455/415 STD corrected.

STD will read higher than SAE. We were tuning to see where we want to see air fuel and timing not a number both cars were rather hot after the last pull and we were fine with it as the cars will see track time. The Titan 4 has run several track days.

Both cars have improved racing crank scrapers / oil pan baffles and callaway honkers. I like the larger filter on the Callaway but would run a Vararam if it came on a car. Hydralock is a toss up IMO.

Heads on both cars had been decked thus the clearance issue also a reason why my cam is only 2 degrees advanced vs 4 I believe on the Titan 4. Less advance is generally better piston to vallve clearance and lower dynamic compression. Being likely over 11:1 static I can give up some compression on 93 octane. Plenty of resources out there to learn how to build these cars.

Measuring push rod length and piston to valve clearance isn't that bad
https://www.corvetteforum.com/forums...arket-cam.html

 

https://ls1tech.com/forums/generatio...dangerous.html

More on flycutting

 

VR tech here- If you go with the Vararam Unit also include the Gen2 Power duct/airbridge to max out the volume. Since you're going with the AFR head you would want to swap the manifold as well. The stock LS-6 manifold flows around 248CFM-252 /253CFM per port, depending on the port at .500in lift@28 in water on the stock LS-6 head. It's best to swap the manifold because you're going to a bigger TB and it's just easier from a time is money perspective.


VR tech

 

Check that NZ shows octane ratings that use the same methodology. US numbers shown on the gas pumps are (R+M)/2 but I think NZ shows only the Research numbers, which are higher.
You don't want unexpected results due to a difference in octane calculation.

Speaking of annoying gas pump markings:

E10 is standard where I'm from in the US but ran across this on a recent road trip. Pump has the standard E10 sticker but ALSO has an E15 sticker and all grades are actually E15. I didn't even notice until I looked at my receipt and it said E15. Then I looked at the pump closely and noticed the additional E15 sticker.