Going turbo on my 355- Cam? Turbo size?

[Birdwick]

Hey I have a SBC 355 with forged crank, H-beam 6" rods, forged Alum pistons, and Edlbrock alum heads with comp rt 9.2:1. Im going to be using a rear mount turbo setup on this motor but I dont know what size turbo, what size down pipe, or what cam to use. I know i need a cam with little to no valve overlap for a turbo but im going to be running low boost prob 6-8psi. Also since its going to be mounted in the back id like the turbo to spool fast but it also needs to not create too much back preasure once i get inot uper RPM. Ill also be using a blow through carb.

I know STS sells these kits but i havent found much technical data.

thanks

[mcasteel2112]

225 degrees/225 degrees duration at .050, .581/.581-inch lift and 113 LSA. pretty evil cam

A wider LSA figure, 112-116 degrees, moves the lobe centerlines further apart and will smooth your idle due to the decrease in overlap. The lower the figure, 106-110 degree, moves the centerlines closer and will increase bottom end but your idle will shake your coffee into your lap.

Id look into that 4-7 grinde l e c t r o n i c - p r . c o m -- New Products: Crane Cams, Inc.
Speed inc can do any custom grind

[Birdwick]

Thanks, I E-mailed STS and they recomended somthing simaler. Ill show these numbers to my machine shop and see what they think. This cars not going to be a daily driver so I really wouldnt mind a rediculous idle.

[Louie L.]

How much power are you looking to make. That will be a better measure of how much cam in general you will need. On a turbo V8 its doesnt take much cam to make a bundle of power. I think you need to figure that out 1st.

On the 4-7 swap , I wouldnt waste much time on it. There are entirely too many cam makers with different thoughts on this . No one is on the same page.

[mcasteel2112]

You would likely see more of an improvement in idle quality and smoothness with the 4/7 swap. no real HP gains but a firing order swap will help scavaging

LSx firing order 18726543
4/7 swap 18736542
LS1 is actually a 4/7 and a 3/2 swap

but all in all the guy above me is pretty much correct plus a 4/7 roller setup will set you back about $900

Camshaft Innovations - Home

OR call guy named Rob Adler. he has worked with both style cams and done dyno pulls with both cams he can inform you on what you want to know. (708-633-1320)

[Birdwick]

How much power am I looking to make?

Well really as much as I can on pump gas. I'll prob run water/Meth so I can run more boost when I want to. Basically I want to make as much power as I as long as the car can still drive itself to the track. I dont care how ruff the idle is, how ****ty the gass milage, how loud it is, or how hard it shifts just as long as I can drive it like I would any other street car.

As far as the 4-7 swap, I like the Idea but I think I already have enought to think about- Id rather keep it simple.

Im going to talk to my machinest and see what he thinks about cam-innovations opposed to what hes thinkin of.

[Dewey]

In this months Car Craft there's a guy running twin TE44s on a mild 350 in a Firebird putting down over 700hp,700tq. Might be some info in this article you can use.

[mcasteel2112]

also last months issue of Chevy high performance, errr its around here somewhere , guy runnin 80 camaro with twins, all custom home made setup but i dont remember anything about the grind on his cam.

i'll look for issue, however I just located another issue with article on the f-body setup rear mount
ststurbo.com
nelsonperformance.com

[Birdwick]

Well looks like Ive got some magazines to buy.

[mcasteel2112]

BW

you should be able to google most articles

just get creative in your search field such as (pros and cons for rear mount turbo system)

or (proper cam for sbc with turbo) etc

good luck

[Birdwick]

I ran the numbers you guys and STS suggested by my machinist. He said he'd get back to me next week with what he thinks I should do.

I'm going through Motor Masters In Hartford, WI. The guy does amazing work but he mainly builds motors for circle track. I don't know how many guys he gets in their looking to do turbo setups.

No matter what the numbers are its going to be a solid lifter cam. At first I didn't want to mess with adj valve lash. But He says his circle track motors need to get adj once or twice a year if he uses thicker rocker studs and stud girdles. Circle track is way more abuse than Ill dish out so I'm not worried about it.

[mcasteel2112]

Solids eh

On my 76 stinkray im runnin a lunati
489/520gl 290/280ad, power band is from 2600 on up i think BUT...... IM runnin variable duration lifters that bleed down .025 & 10d so its still ugly at idle but i can drive it..although a little too big if you ask me for trip to store. I did have blower on with proper cam but got hair up my a$$ to do away with it. thats when i went to this cam which is ok and it pulls hard but not what your looking for.

[Blazer406]

I have a 224/224 .541/.541 on a 112 CL custom grind solid roller from comp cams race shop.

It is a real small roller.... was cut for a 383 ci turbo motor... to make max power at 6000 RPM's.....

Brand new... never installed... still in box.....

Don't need it... bought a 231 ci 6 cyl... before I had a chance to build the engine....

$150+ shipping...

non billet... austempered core I think.... regular distributor gear will work.... doesn't have to be bronze...

Sorry for the thread hijack...

Just thought you might be interested.

[Birdwick]

Thanks Blazer but Ive been keeping him tied up long enough looking for parts Id rather just have him order something.

I read the article in car craft about the 88 TT Firebird. I'm putting this motor in a 88 GTA Trans Am, same as that guys! The look of that car is exactly what I'm going for. I love how he cut holes in the front bumper cover to get more air flow. Its functional and it looks awesome. Most people just laugh at 80's f-bodys cause there usually rusted out slow piles. But when you do them right I think their one of the best looking cars ever made.