I believe this may be my very first forum post... so I'll try not to bugger it up.
I've been a humble member for a few years now, even though I have yet to purchase my Vette (C6 GS M6 in Cyber Gray, 2-tone interior). I've had MANY performance cars over the last 40 years or so, mostly late 60s muscle cars, although I did own a C3 back in my mid 20's (was a real nice 72, but nothing special, but it was indeed quite a pretty car).

First I confess to be a big fan of several on here, have copied several 'dozens' of various postings, and all the interesting/insightful responses on certain topics. One of my favorite sources is Mr. SpinMonster and aaaall his info on cams, engine mods, heads...etc. I haven't dug very deeply into him, but do wonder what his name actually is, what his business is, and how he seems to know all he knows, and about so much...? Maybe someone can please fill me in or send me where to find out?

Anyway - Some of the info he's shared over the years will be the main focus of this posting, for I have "questions", and seek the wisdom of the forum for guidance. My hope is that perhaps SpinMonster himself will make an appearance, and answer them, but I'm certain there are MANY on here who could also be equally informative. Anyway - Here goes -

1) With all the aftermarket heads available for the LS3, WHY does he seem to push the Trick Flow heads...? I don't recall him recommending any other brand of head, and there are soooo many.... WHY? ...what am I missing?
2) Using his now legendary 230/234 114 cam and the Trick Flows, it's should render approx. 11.5:1 compression, which I know is a win-win if it'll work... "but how is that level of compression even possible with the crappy alcohol laced pump gas we have without detonation/knocking?" Perhaps there's a 'knock sensor' at play to make it work, but wouldn't that really rob power..? I'm no rookie to all this, but ... well... I've no experience with an engine like this LS3, and all its electronics, computers and sensors out the wah-zu... So?
3) By upgrading to the TF heads (or other brand), the valve angle shifts to 12 degrees, thus no more Piston-to-Valve clearance issues. Q: Using his cam, with those heads = "Why can't the cam specs be pushed up a bit, say for example: 234/238 and .635"/.618"...like that..etc..?" Not saying I'd do that (don't want a race car these days), but seems if things can safely be pushed there, and still maintain the intent of that cam, why not do it? It would render even more power... no?
4) My last question for this post: Does going with a larger throttle body reeeeally make that much of a difference (HP/TQ) vs the expense$?

Okay - I'll check this occasionally to see if anyone takes the time to teach this 60 year old "used to know it all" motor-head about this truly outstanding power-plant and all it has to offer. Hoping so.

Oh & BTW - I need to sell my just finished project to help finance my new Vette - here are a few pics.

1972 Plymouth Duster

Very nice graphics

Nope it no Corvette, ha...

408 Stroker, dyno'd 529 hp 514 Tq at the crank. Nice lil eye catch'n streeter.

 

Welcome to the forum. There's more than a few of us "seasoned" members around here. Nice Duster you have there. What are those funny looking things on top of your engine? My '69 Camaro has just one big one.

1. 11.5:1 CR is no problem with 93 octane fuel....no matter the ethanol content. Lots of good cylinder head options available for the LS3. You can spend a bunch on aftermarket castings and have them worked all over if you have the cash and want to invest it there. I recently did heads and cam with just the porting of my stock heads. $750 vs spending a few grand on the top of the line heads. The big money heads can make more power no doubt.

2. Lots of cam options for LS3's. Cams are a compromise and you need to decide what's important to you. If you want big power and don't mind degrading your driving manners, you can go WAY bigger than Spin's cam. If you still like a smooth running Vette, look to the milder cams such as Spin's. I went milder yet as I've had big cams before and want no part of them. I enjoy near perfect manners and decent fuel eco.

3. You can push way past 234/238 .630 lift even with stock heads.

4. I think a bigger throttle is a waste of money on a stock cubed LS3. Have you stock throttle body ported for increased throttle response with maybe a horse power or two thrown in for good measure.

Do a search for "heads cam" and lots of stuff will come up. My build thread is there and it's not too many months back. Good luck on your build and enjoy the ride!

 

Nice Duster.

Regarding question 2. The combination of port fuel injection and computer control provide much better fueling control to reduce detonation. Having computer controlled timing rather than mechanical timing also helps greatly in maximizing efficiency and reduce risk of detonation. The knock sensors are there if something goes astray such as bad gas, using too low an octane, mechanical failure. Under normal operating conditions, the tune is set as aggressive as possible to maximize fuel efficiency, power, and emissions while avoiding knock.

Regarding question 3, if I recall Spin's old posts, his point was the 230/234 114 with a mild compression bump was the sweet spot for a daily driver with stock LS3 heads. After swapping cams, he found the very small gains of going bigger on the camshaft weren't worth the drivability trade-off for a street car used in a dense urban area. Plenty of people do run bigger camshafts on LS3 heads if their goals are different or if they have the time/ability to tune out the low rpm problems of a big cam, or if they simply don't mind a little bucking in the off-idle rpm range. Cams for aftermarket heads are best optimized to the specific heads used.

Regarding Q4: A bigger TB becomes more beneficial the more mods you do. There are other mods with a better HP/$. If you are spending the money on heads, aftermarket intake, a big cam, then I would consider it as part of that package. I have stock heads and intake manifold (ported), along with a mild cam. It wasn't worth the cost for me.

 

Thank you for the responses - much appreciated!