moneyman380

-forged crank, h beam rods and SRP flattop pistons, balanced
-plasma moly file fit rings
-all arp bolts
-4 bolt sbc 350 truck block
-clevite 77 bearings
-high volume oil pump
-Dart pro 200cc aluminum heads with minor port and polish work, and gasket matched
-Accel superrram with 1000 cfm throttle body
-double roller timing chain
-Comp Cams CS XR269HR-12 , Duration 218 224, Lift .495 .503, Lope Sep 112

Plan on running my N.O.S. plate along with a fogger setup later.


Just wanted to get some opinions on my cam choice and any last minute changes that should be made.

1991 RS/SS

Looks pretty nice. I personally would ditch the HV oil pump.

Just curious, while you are going this far, why not go stroker?

moneyman380

Well i originally went Twin Turbo BBS designs headers and turbos and in the process i had a 355 built at my machine shop with low compression pistons, all forged. So when i changed my entire setup back to N/A it would be far easier to swap pistons than buy a stroker kit and then have my block machined for a longer stroke.
But since my orignal blower setup was balanced i decided to just go ahead and buy another complete rotating assy already balanced with the higher compression pistons that i needed. So if i could only go back in time.... i would have went stroker and then i would not have a sh$%load of extra parts laying around. But my plate nos (150 shot) combined with my fogger (up to 300 shot if i want to grenade my motor) will make up for the lack of cubic inches

Also i did not mention that i will be running 10.3 c/r.

JesasaurusRex

iTrader: (3)

why such a small cam?

moneyman380

I thought it was pretty good cam coming from stock Lift .413 .428 Dur 202 207 and i was told it works well with the superram.

Well what would you go with ? because i have not put it in yet, waiting on a degree wheel

1989GTATransAm

iTrader: (3)

Seeing as you will be running NOS that changes things. I would call the cam manufacturors for their recomendations.

Evil 88IROCZ

I would ditch the high volume oil pump. I would use the stealthram instead of the superram. That 1000cfm throttle body is to big for what you have I would use the 52mm. Heads are ok however I am totally sold on the AFR 195s. The cam is way to small my 305 has a bigger cam and it drives fine. I would use at least 222/230 509/522 112 from crane. Just my two cents.

1989GTATransAm

iTrader: (3)

Let's do some math on what size cam you need. Let's start off with a 6000RPM goal.

CFM requirements. 355x6000/3456=616CFM
Divide by 8 cylinders equals 77CFM per cylinder.
Lets say your heads flow 260CFM with intake. Thats alot.
X= 77/260 X=.296

The cams need .296 of 720 degrees of duration which equals about 213 degrees. Sounds like your selection of 218 degrees is a good one with some wiggle room. If your heads can handle it I would look into the Comp Cams XFI 268.

What are the exact intake and exhaust flows for the head say at .500 and .600 lift?

JesasaurusRex

iTrader: (3)

getta custom grind, call crane,comp,isky ... call somebody they can even recommend you one that they already have.

moneyman380

I called comp cams and thats why i bought the one i did, they recomended it. My other choice was a comp 280XFI HR13 Lift .576 .571 Dur 230 236 Lobe sep 113 that my machine shop told me to get.

moneyman380

Called comp cams again today and they told me if i wanted a bigger cam to go with their 280XFI HR13 Dur 230 236 Lift .576 .570 Lobe sep 113

or CS XR276HR-12 Dur 224 230 Lift .503 .510 Lobe sep 112

Im trying to match a cam that will run with a stock converter untill i have the money to upgrade. Im going to order a new cam tomarrow for sure, so any help narrowing the choices down would be great.

Also the heads flow 264cfm intake @.500 and 180 exhaust @.600, from darts website.

1989GTATransAm

iTrader: (3)

More math. 180/264 equals 68% on the I/E flow ratio. You will definitely need a split cam. You can custom order an XFI cam with a 224 degree on the intake. Lobe number is 3015. The exhaust side lobe 3038 which is 230 degrees. I would stick with the 113 degree LSA for fuel injection. Double check all this with Comp Cams.