My setup is 383 ci eagle Forged, 6" rods, TEA LT4 heads and intake CNC ported (#'s below) they have 2.05, 1.60 valves. 12.8:1 compression, Th 400 with a trans brake 5500 stall, Ford 9" with 4.56 gears, this is a Race only setup I tried hyd. roller and was not impressed going to switch to solid roller. My ? is who do you go and trust? Comp, Crane, Lunati (keep in mind crane tech stuck me with a horrible cam). If you go custom who do you guys suggest?

What cam works for you guys that might have a simalur setup.

head flow #'s
int. exh.
.100 - 71.4 60.4
.200 - 139.2 120.
.300 - 198.3 166.1
.400 - 245.3 200.9
.500 - 283.4 230.
.550 - 296.2 239.9
.600 - 301.3 248.8

Thanks in advance!

 

I have a fairly similar setup. I worked with a builder who got this grind from Comp Cams. It is a solid roller spec'd for 300 shot of nitrous. Intake centerline is 114, Lobe separation is 114. Duration at .050 intake 260/265 exhaust. lobe lift is .393/.400 with my 1.6 rockers that works out to .629/.640 lift

Valve timing
Int. 16 BTDC 64 ABDC
Exh. 66 BBDC 18 ATDC

I'm using this with some AFR 210's. I have not fired the engine yet.

Rick

 

Wow, some kind of air flow! Are you purely NA or will you be using nicetrous?

 

Have you personally had these heads on a flow bench or are these the advertised numbers? May be why the cam you have doesn't work so good. The numbers "seem" a little high. If the cam was spected to these #'s and you are not getting that much flow it could run really lazy.

 

I am NA and would like to stay in that area if possible the cam I have now is a 509/528 + my 1.6 rockers the duration @ .050 is 248/252 @ 112 LSA I don't have the spec card in front of me but I will post the degrees of when the valves open and close

yeah these #'s have been confirmed on TEA's bench and a "local" flow bench
I have just got these heads but I was running this cam on a set of ported LT1 heads and the cam didn't work with them so I know it won't work with these new LT4's

 

Thats a strange cam. You need to get up into the 260@50-108+4 range and a lot of lift and it should fly if it has the compression.

 

here's all the #'s on the cam could it be just a bad grind from Crane???

I was a little off on the lift.
int. exh.
474/510 with 1.5 add 32 with my 1.6

cam timing @ .050
intake opens closes max lift duration @ .050
23* BTDC 49*ABDC 103 252.0
exhaust 65* BBDC 19*ATDC 113 264.0

should I keep my 1.6 rockers if I go with say a 670 lift cam (I know I have to check for clearences but would there be any gain or would it hurt more then it helps)

 

no doubt...i bet its a high-revver! 260/265 on a 114 with no advance ground in...

 

I dont think that's the duration at .050"lift: That looks a whole lot like ADVERTISED duration, and it looks more like a mild street performance cam. You're probably in the 212/218 degree @ .050" lift area than anything. That's close to the cam specs I run in my street 305. However, it's weird: .510 inch duration on a 264 AD duration lobe seems kind of high for a hydraulic roller. The .474 inch lift is what I'd expect on a 252 advertised duration lobe though.

I'll bet you have a nice, smooth idle and 12 to 14 inches of vacuum?

Try Comp Cams P/N 12-773-8. Solid roller cam with an operating range of 3000 to 7200 RPM. They will get the valve lift into the .600 inch lift area.
254/260 deg @ .050"lift, 110 degree lobe separation angle. .582/.588 inch lift on a 1.5 ratio. Comp's catalog recommends a compression ratio greater than 11.0:1, and a 3500 RPM stall, which you seem to have. You'll probably need Comp's 977-16 valve springs, and their titanium retainer and 10 degree valve locks, as well. The 977 is a 1.46 inch diameter double valve spring with a 441 lb/in spring rate, and a 155 pound pressure on the seat when installed with a 1.850 inch spring height. Can your valves and cylinder head spring pockets handle that?

 

actually the 252/264 is at .050 I have a horrible idle with about 5" of vacuum at 1300 rpm which is as low as I can get without it wanting to just load up and die (and it not cause of my tuning my tuning is good)
yeah they already have the comp 977 with Ti retainers and locks

 

Hmm... I guess I'm out of suggestions!
Your stated valve lift suggests a cam of much smaller duration, especially if its hydraulic roller. Your published IO IC / EI EC values also point towards a cam of much smaller duration. Yet with super-choppy idle, low vacuum, & use of 977 springs points towards a big cam. It might be in your best interest to pull a valve cover and, with dial indicator mounted on the rail, roll over the engine by hand to manually measure the actual intake and exhaust valve lift. It it's really only about half an inch, you probably should pull the cam to see what is going on. Did you degree in the cam when it was installed yourself, or did an engine shop do it for you? Where is your intake lobe centerline located?

[edit]: Okay, I did find an obscure set of flat tappet lobe configurations called "lift rule" lobes that have valve lifts and durations like what you suggest: There are a class of lobes which are used Stock eliminator classes of NHRA, among other things. Is your race motor set up for some kind of race class with a rule concerning valve lift or duration?

 

No I am not regulated to any certain valve lift, just regular "Pro" bracket racing, and yeah I forgot to mention that it is a "stocker" type cam but I didn't know what we were getting from Crane just trust the tech department (now knowing that, that was a mistake.)
This is a roller cam as the factory LT1 is a roller cam engine.
I guess do you have any suggestions on where and what type of solid roller I should be looking at?

 

So this is a drag race, competition LT1 engine. Are you running fuel injection, or have you converted to carbueration? What's the weight of the car? If running EFI, what kind of ECM are you using, and is it SEFI, batch fire, speed density or MAF?

These questions need to be answered before any cam question could be adequately answered. Have you tried calling Comp Tech help yet?

 

Converted to Alchohol Carburation
The weight of the car is 3200 lbs with me in it
let me know what oter info I need to put out

AIM: WIDOMKR383

 

If you get in the .650 range on lift with the above spects and kick your dynamic compression up to 9.5-10.0 to 1 with the alcohol it will show you something.