Alright after a ton of searching i want the opinion of you guys out there running twins. Im trying to finalize my cam selection but am having trouble cause i wanna get this right the first time.
After searching through both comp and cranes cateloges i figure it will just be easier to go with a custom grid. So far im thinking along the lines of 240/248 .543/.561 112 in a solid roller. Any input you guys can give would be great. thanks

Heres what im running:
383 motown race block with eagle internals and srp pistons at 8:1, Afr 195's with competition port job, stealth ram ported, twin t62s, T56 trans with 3.73 out back

Now the fabrication on turbo system hasnt started yet but im hopin to start in the next few weeks. Im lookin for about 800plus rwhp while still being some what streetable.

 

cool, a BC guy...anywho i'd get a custom cam ground for your combo

 

You won't need that much cam, much less a solid roller.

 

around a .490-5.20 lift should be all u need and u should probably go with a hydraulic roller over a solid..

 

I would go with something like a 232/228 at .050 .550/.550
lift hyd. roller ground on a billet core with a pressed on gear, with a 114 degree LSA...this should be plenty, imo...

 

None of those suggested are even close to what you need.
Run any amount of overlap at all and you will lose power with a turbo due to the backpressure factor. Run any extended intake duration like as suggested and you will have huge pumping losses.
Short intake periods with wide lobe seps and healthy split in favor of the exhaust are what turbos like. That's why stock cams work so well in turbo applications. You simply cannot spec a cam for turbo the same as you would for naturally aspirated, or even for a blown or nitroused engine.

Do yourself a huge favor here and contact David Vizard for a $35 cam spec for your combination. It will be well worth avoiding all the trouble you're about to cause with the improper cam selection.

 

I htought those suggestions were a bit small as i was runnin a hydro roller 230/236 .510/.520 on my blown 355.

How would i get in touch with David vizard??
thanks for the suggestion guys.

 

Read this:
http://www.digitaleveryware.com/pipe...ne/001129.html

There is info and phone numbers for his machine shop. This shop uses the same software and methods to spec cams as Vizard himself.

I believe you can find his email here, though I have not tried to email.

http://www.coe.uncc.edu/college/vizard.htm

 

www.cammotion.com

 

i tried the links posted to get the order form but they are no longer valid so ill just give the shop a call monday. Thanks for the help.

 

I think they will recommend something pretty close to what I posted above...there is engines with similar builds to Yours
over on turbomustangs.com making very good power with cams like that...most of them get their cams from cammotion... Please post what they recommend...I would like to see how much I was off by...

 

So the recomendation is in. I got it not from David Vizard himself but from Denny at motor machine and supply who designed the cam selection program with David. My guess was the closest, we can up with 298/316 advertised duration and .615/615 lift. The profile that we worked out is a little smaller than the program suggests but id rather lose and few ponies and have a more streetable engine.

 

I don't know what to make of this...it goes against most things I have ever seen concerning turbos...that is pretty much a blower cam. For 800 rwhp...its huge, imo...
I put a cam like that in a BBC with an 8-71...twin turbo smallblock...It just don't seem right, but who knows...I may be totally wrong. I would get a second or even third opinion on this if I were You though...just to make sure...

 

i noticed that you wanted to stay pretty streetable whioch would obviously mean you are driving this on the streets. any reason you are going with a 383 over say a 355 that it sounds like you already have? IMO i would stay with close to stock cubes and let the turbos do their job. sure you can make more hp with a bigger engine, but you will make WAY more torque, something that turbos make plenty of regardless. something to think about if you havent bought your parts yet.

 

Please post the .050" numbers, exact opening & closing events, and LSA as well.
Advertised numbers can be very misleading and useless by themselves.

With a turbo you can have a lazy intake opening ramp, but the exhaust needs to be quick, so the .050 numbers should show much wider normal split.

The reverse split posted by Tommyt looks more to me like something designed for a Ford race head, not a factory cast SBC head.

Also to note a friend of mine has been driving with .630" lift daily for a year & no problems.

 

Do a search on Turbomustang for INTMD8.
He built a similar combo and did lots of cam testing.
He ended up running a CC 219/219 1.6RR on a 114lsa.
With T61's and .58 OC exh. and 18 psi boost.
It had the best manners and still did 800+ rwhp.
You might go slightly bigger with the 383.

Cammotion rec. to me a 221/219 115 lsa for a similar 355 for shifting in the 6000-6500 range.

 

I recommended a reverse split because he has AFR heads and wants a street motor. Also, my understanding is that the reverse split is better if the engine has a restrictive exhaust system ie. log manifolds instead of tube headers, small A/R turbines etc., typically found in street motors. There can be a lot of variation in different setups. Some people run the same duration on both sides, but different lift, or even the same lift too, with a different lobe center etc. In retrospect, tho, I suppose my recommendation is still a bit on the big side, but not by a whole lot...it would depend on the combo, trans, gearing, weight etc... And of course I am no expert either.
But its still better than that blower cam, imho...

 

Huh… interesting, I’ve been mulling over a similar recommendation for a similar engine from cammotion, 221/214/115 ground 3* advanced rather then the normal 4. It threw me for a loop because it is significantly different then what I expected and what everyone else was suggesting, which was something right around the limits of what the hydraulic roller lifters would tolerate, something more like Comp’s recommendation of and XE 236/236/114 or 115 (I asked them about my thoughts, 236/230/115 and their answer was that it would make more power but would be a problem on the street).

I still don't know what to make of it...

 

.050 numbers are about 235/255 with a 112lsa. Their not exact but should be pretty close. I dont have the exact numbers since we played with the lift numbers and that changes the .050 numbers.
Also the cam is a bit big but we decided to shoot for a little over a 1000hp instead of the orginal 850 i wanted. Its not like a plan to drive her everyday, just sunny dry ones every now and then.

And the exhaust will be far from restrictive. The cars getting tube headers, the turbos got an .69AR wheel, and the exhaust is dual 3" all the way, dumped b4 the axel with no mufflers. Thats the plan neways.