Priya

I'm building a Vortec/TPI 350 motor. I have Arizona Speed and Marine large runners and planning on using 24 lb injectors. With the 64 CC Vortec combustion chambers my motor will have 10:1 compression ratio. After a lot of reading and looking at other people's builds I had planned on using the Iskenderian roller cam below:

Intake .485 lift, 217 degrees duration at .050
Exhaust .505 lift, 225 degrees duration at .050
Lobe separation angle 112 degrees, 44.5 degrees overlap, 8.00:1 dynamic compression ratio

The heads I'm looking at buying come with valves, springs, etc. and have a max lift of .480 inches. As budget is a concern I'm looking at the flat tappet cam below as it doesn't exceed the max lift of the heads and won't require me to adapt my 79 350 to a roller cam.

Intake .477 lift, 224 degrees duration at .050
Exhaust .480 lift, 230 degrees duration at .050
Lobe separation angle 114 degrees, 45 degrees overlap, 7.90:1 dynamic compression ratio.
Manufacturer's note: "Best cam for modified 350 TPI with improved chip, injectors, plenum, runners and exhaust."

As I've never tuned a fuel injected motor I'm hoping to use a stock 350 TPI tune on my EBL or at least not have to deviate too much from stock to get the motor running properly. There's quite a bit more duration on the second cam than on my first choice. Will this be too much duration for a good quality idle and driveability? Will the second cam require a greater amount of tuning from the stock settings than the first cam?

cv67

Id use the first one call Summit get their tool to cut your guide down its cheap. Then make sure your springs are set up right

TJ Wong (wongs performance) can get you a chip thats very close, one or two others here are good at it. Like to see how that Isky runs always had good luck with their products.

Priya

If it was just getting the heads to work I'd stick with my first choice as well. But its also the second cam is a flat tappet and then I don't need to convert my 79 350 to roller lifters which I think is quite a bit more expensive.

I have an EBL flash so I'll be doing my own tuning

JackDidley

Those cams are mild enough to work with a TPI. I have a ZZ4 in my 87 with stock heads and TPI. Runs like it should but it shifts at 5k and the ZZ4 will pull to 6k, no probem with heads and a Miniram.
ZZ4 - Hydralic Roller - Part # 10185071
109 degree intake centerline, 115 degree exhaust centerline.
112 degree lobe seperation.
Duration @ .50 lift
208 degree intake, 221 degree exhaust.
.474 intake lift, .510 exhaust lift.

Priya

That sure is a lot of difference between the exhaust and intake lobe profiles!

ghoastrider1

yes on the second choice. I would be worried about valve seal crush with the lift you are going to run, its really close. Your "cheap" way would be to buy some "bee hive" springs, with the retainers. I think they are around 300 bucks. Don't need to cut the spring perches then with that second cam. That motor will like the 114 separation and you might not need a tune with that cam.

Priya

Just what I was wondering

cardo0

Sorry to say but I think both cams will be down on power w/stock tune. The second cam ain't giving u a thing over cam no 1. It may run to higher RPM but not any more power than cam no 1.

BTW guessing at compression ratio using published numbers is just that guessing. If u want accurate c.r. numbers u need to measure it w/liquid.

If u are money tight then find a shorter duration flat tappet cam. I don't see how u can justify a large duration cheap cam now that roller is to expensive. A vortex head is an economy head that does a good job for the money. The AS&M intake is a good idea but u need a cam to match your low lift heads and the engine compression. I really think u are going the wrong way in cam duration and cost. Make the combination work together. I like the 112-114 LSA but keep the lift under 0.500" and full duration under 280 and closer to 275 degrees.

What kind of exh do u have?

Priya

I didn't expect the second cam to make more power than the first, I actually figured it would make less. My first choice for cam does not exceed .500 lift on the intake and only exceeds it by .005 on the exhaust, the second is well under .500 for both. I don't know how full duration at 275 compares to duration at .050.

edit: checked both cams, the first is full duration intake 265 exhaust 272. The second is full duration intake 268 exhaust 280. So both cams are basically within the specifications you've suggested. I won't be sticking with stock tune if its not ideal, I just was hoping the stock tune would be close enough to get me driving it so I can gradually work on the tune.

The exhaust will be rams horns manifolds, dual exhaust, no cats with an H pipe.

cardo0

I find those duration numbers unbelievable. Please post the part numbers.

U have fairly restrictive exhaust w/o any savaging. I would use at least 10 degrees more exhaust duration than intk (full duration).

Priya

The first cam is an Iskenderian part number 201265/272 grind number rr-265/272

The second cam is a Comp Cams part number 12-268-4 grind number XE268H

cv67

This? would run great with your tpi
would it run on the stock tune probably I wouldnt other than to pull it in/out your driveway.
It will run strong with your TPI.
Use Iskys lube on the cam too if its the same stuff they used to use, good stuff. + lifters . Best FT lifters on the planet are GM..if you can find a pair.

http://www.wongsperformance.com/

ghoastrider1

this is the cam I purchased to run with my Vortec heads... https://www.summitracing.com/parts/cca-12-404-4
I wanted something I could run without a tune, for a while anyway. By the way, while your at it, you might want to change to a high flow water pump, most of the stuff will be out of the way anyway.. since you are going to be buying a new timing chain.. right? Oh, wait, if your running a roller engine already, this cam isn't for you.

Priya

Yes, the more I think about it and with what Card0 said I'm thinking that really is a better choice. I just don't like the extra cost.

Priya

I'm not running a roller engine. Thanks for the suggestion.

cv67

you can still run a FT cam in a roller block if moneys that tight just make sure you get quality pts and a good lube. Since GM quit having those lifters made its dicey. I wouldnt trust most aftermarkets never know where its coming from. Pay me now or pay me later thing FT vs roller

cardo0

Both those cams are more aggressive than i expected. I dont know how u calculated the dynamic compression w/o the full duration number but u are on the low end of the range for a performance motor and throttle response will suffer. It reads like u are not going to spend for a roller conversion so that pretty much kills cam no 1.

FYI 0.005" doesnt look like much but in reality u need a margin from coil bind and most cam mfr recommend 0.060". How that is determined varies greatly due to how aggressive the lobe ramps are - but thats my assumption so take it or leave it.

I like ghostrider1 cam recommendation. I think thats a better match for your engine, compression and budget.. If u think u need more lift then u can always try higher ration rocker arms. U will need to take added precautions to break in a flat tappet cam so be ready (they will wipe in less than a minute if not done correctly).

Good luck and post your results as it helps us all.

383vett

Run the roller and not the flat tapper if at all possible. There is so much of a power under the curve advantage with a roller over the flat tappet, even if the cams have the same identical specs. If performance is your goal find a way to go with the roller.

Priya

Are you running long tube runner TPI?

Priya

http://www.wallaceracing.com/dynamic-cr.php

The cam ghostrider1 recommended has a 7.96:1 dynamic compression ratio so its basically the same as the first cam I posted. I thought the dynamic compression ratio of both cams I posted was a bit higher than desirable for a car running on pump gas. Ideally I'd like to run on 87 octane but if a higher octane is needed I'd live with that.