Abubaca

iTrader: (3)

I'm starting to research by buildup here lately. Since I'm ****, I wanna keep a long tube set-up. Hogged out aftermarket is fine, but it's gonna be an LTR. Also, block needs to match. That's means 2 bolt mains, probably freshened .030 over, but nothing radical.

The question is where to stop with the other parts? How much cam is too much for a hogged LTR? And for that matter, I don't wanna go toooooo ridiculous on heads either. No need for some killer ported AFRs on this motor. I was thinking maybe an hotcam "ish" sized cam with some vortechs, maybe some mild porting.

No need for exact parts here, just looking for health discussion! What are some of your ideas, opinions???

1989GTATransAm

iTrader: (3)

I'm sure you have seen my hogged out SLP runners. They will flow tons of air. With the Extrude Honed Edelbrock Manifold I would say the combo safely flows 270CFM.

Regarding the cam I would not go less than 218 degrees on the intake. I like the Comp Cams XFI series although there are other goods one on the market with high acceleration rate lobes. As to too big I'm sure a 230 degree cam would work and would be about as big as I would want to go.

Regarding the heads Vortechs are very good. I would say a 200cc head would be about the limit I would go. Look for a good used set of heads and go from there with a professional port job.

Go with a set of 1 3/4 inch headers for a 350+ motor. You will need a good free flowing exhaust system.


Regarding the block I would use hypereutectic pistons(no N2O) with the powdered metal rods. I have found goods used ones pretty cheap. I would build to 10.5 compression or so with aluminum heads. If you keep the quench around .040 you will be allright for power and detonation. Enough rambling.

Abubaca

iTrader: (3)

OK, see I was thinking those parts would be WAY too big. Not that I'm an expert though.

I was looking at possibly the LPE211/219 cam with some hogged out vortechs under some sort of LTR. Seems to be most are saying for a LTR you wanna stay away from anything over 220. Even the infamous Super ram/AFR190/383ci motor doesn't go that big. (219/219)

This will NOT be a track motor. It's a street motor so peak isn't important. I'd rather be a tad small than too big ya know?

Again, this is why I'm posting. ideas, ideas,ideas!

3.8TransAM

Comp 212/218 and 218/224 duration grinds seem to work pretty damn good in long runner setups.(Kinda wished I used the latter in my built for boost 383 buildup, guess we see once its huffing)

Makes for a pretty good torque peak.

If going on all out max LTR, I would go hogged/worked aftermarket base w/ SLP runners + extrude hone them.

For all the though you might start looking at a FIRST setup, might end up being cheaper in the long run.

Heads I dont have favorites, well I do, but the biggest factor bar none is what u can afford to buy. So buy as best a head as possible. Vortecs are a great cheap choice, AFR's are better if u can swing it(and no custom base for the heads)

Work on learning how to tune now on a stock engine, rather than learning how to tune on an already modified engine.

Good converter is worth the dollars as well. I love my vigilantes, they truly are worth the extra 3-400$ over a stocker restalled.

Or do something different. Run a cam in the range we have mentioned and get your stock heads, base and some aftermarket runners on there and extrude honed. Would be interesting to see.

Above all, shoot for what your true purpose is. U can go bigger on everything if its a strip and/or toy car. If you planning on daily driver or just cruiser, you would be wise to err smaller.

later
Jeremy

Abubaca

iTrader: (3)

Thanks for the input!

....The plan is like you said, SLP runners, ported plenum/base etc. The first system is .....sheeesh, just plain ugly. Like some sort of botched genetic experiment. I just threw up a little in my mouth actually.

I'll have the T56 in by the time this all happens!

....this is strictly a toy, but still a street car. I have no intention of making this a track car. Several of the locals have 500+ HP LS1 cars so this isn't a contest, I just a want a fun pavement stomper! I'm thinking around 300 rwhp, give or take a little, some deep gears behind that T56, and a torquey LTR set-up.....that'll be fun!!!

New question, and this is a BIG can 'o worms. How does duration vs. lift play into the LTR scenario? They seem to be more sensitive to duration, good AND bad, than they do to lift. ....from what I've read....

SOEZ

From what I've read and tried, its easy to over-cam a LTR setup. Velocity is key in these setups so heads with intake volumes larger than 190 should be avoided for a street application LTR. Heads with 165-180 intake port volumes with good flow characteristics work nicely to maintain velocity and give you nice street manners.

If your heads flow nicely on the intake and exhaust side(I/E ratio of 75% or more), a single pattern cam in the 220/220 range would complement this setup without being a slug around town.

Use your head flow data to determine max lift. If max CFM is achieved at .550 lift (on the intake), pick lobes/rockers that put you around this area. Same thing goes for the exhaust side of the equation. As long as your heads continue to gain CFM at lifts greater than .500, use it to your advantage to maximize this setup while keeping duration lower (220 or less).

Clutch_Grabwell

Abubaca, could go into more detail on what you mean by some deep gears behind that T56? I caught a ration of poo on another board after mentioning that my GN rear (3.42:1) was going in and the stock 3.73 was coming out.
My L98 has been improved but isn't intended to be a world-beater. I picked that rear because it will live longer and for that ratio.

Mkos1980

iTrader: (8)

I ran a 383 TF Heads Edel Intake, ASM Runners. and the LPE219 cam. It was good for 12.76@106 with 318RWHP and 424 RWTQ

Abubaca

iTrader: (3)

Mkos, when you say the LPE219 cam, you mean the true 219/219 cam right? Sometimes I see the 211/219 cam refered to as the "219" cam, but I don't think that's correct. Anyhow, NICE numbers!


...as far as gears are concerned, I'm thinking about running a 3.70 gear in my BW 9bolt. Currently I have a 3.27 in the 9 bolt w the A4. I know lots of people running 4.10 gears with the T56 since it has a double overdrive gear, and they still have great cruising RPMs. Problem is, several of those people I know didn't actually see a ET change, and some went slower. Some also say that on the street, it's almost too much. In my opinion, I think I'd rather have your 3.73 than the 3.42, but it's all what works for you.

3.8TransAM

If your staying long tube I would prolly stay with the stock rear or maybe go with a 3:42 if you have to rebuild.

Figure out how your going to be driving it and launching it at the strip and gear accordingly.

Most good running stock 350(assuming good gears aka 3:23-3:27) are high 4k -5kish rpm crossing the line.

later
Jeremy

91Z28-350

Follow what SOEZ says. Pick your heads first. Then pick a cam that maximizes the flow rates given the head and the intake.

Going with a cam that has .600 lift while your heads max out at .500 lift and goes turbulent above, is a bad idea.