I need some help wrapping up the parts pile for my 305-350 swap this spring. I have been gathering parts for a few months now, but I have a few questions on the final few. I am running a non-roller 355 with flat tops. My compression ration is going to be near 10:1. I am using stock vortec heads with screw in studs/guides/beehive springs. The intake is a holley stealth ram.

The cam I plan on using is comp 268XFI H13. I wanted to be close to hot cam specs, but using a flat tappet. Specs are 224/231 @ .050 with .520/.515 lift using 1:6 rollers, which I have.

I guess my question is with the HSR my powerband is going to be higher than runnin a stock or modified TPI set up. The cam/intake/head combination should produce good power from 2,000-6,000 rpm's. My car has the stock 2:73 gears with a 700r4. What do you guys feel would be the best gear ratio and stahl combination?

This car will be a dd in the summer (weather permitting) so I don't necessarily care about leaving the line at 3,500 rpm's to get the absolute best 1/4 mile time. I do want to have the stahl/gears/powerband matched together to create a complete performance package.

I know there are a lot of you on this forum that have first hand experience here and I do not. I do not want to end up spending money on parts twice, and even more than that I do not want to take things apart once my swap is done!

If I missed any critical componets needed to answer my question please let me know. I know the more I provide the more accurate your answers can be! Thanks, this forum has been a great help to me!!

 

I'd suggest a converter with a stall (not "stahl") speed of around 2500-2800 RPM, and about 3.42 or 3.73 gears. With lockup of course. Other people with simialr combos have got good results with stuff in that range.

 

Will a stall that high be friendly on the street? I have read that higher stall produces more heat when you're just running around town, which I will be doing quite a bit of.....

 

Also, how do you feel about that cam? I get mixed messages about vortec heads and which cam to use. I could go bigger, but I'm not sure if I would be doing any good or just have bigger lift and duration numbers to tell my friends about. It seems like the hotcam/vortec combo has proven to be a pretty stout combo. I don't wanna "fix what isn't broke".....

 

Here's a thought - might be a bad thought - I'll let the more experienced members tell you yay or nay ....

I installed a converter from a 6cyl S-10 pickup - it stalls at about 2200 rpm's behind my 350. Not sure what most would consider "street friendly", but it does fine for me - I'm not racing anyone, just cruising the streets like you mentioned, usually my road time consists of running to local cruise-ins and car shows. I've had it in the car now 3+ years with no issues. The reason - cost - I got it from GMpartsdirect.com for $125 shipped. I'm not one to spend twice as much for a brand name - especially on something unseen. I'll agree that usually you get what you pay for - but in this case I couldn't see spending double+ cash for a B&M (or whatever brand) that stalled at only 300 rpm's higher.

There used to be alot of discussion on TGO about using the S-10 converter on a 350, not so much anymore - but a search should yield what years/motor size to look for (I don't remember). And, might not be an issue anymore either - maybe the S-10 converter has come up in price or something and thus nowadays it doesn't help - but I thought I'd throw it out there for you. Never hurts to save a buck if you can (especially with $3+ gas now and climbing).

And gears - I really like the 3.42's that I have - nice "get up and go" gear for the street (might not win any races, but feels nice), but slightly more wallet-friendly on the highway mileage than 3.73's.

 

I will definately look into it. This is why I posted, to get first hand experience. How much hp do you think you are pushing and what rpm's do you run at 55mph with those 3:42's?

 

BUmp for the evening visitors!

 

I have no idea on hp - old 350 but nothing special. Everyone says my tach is off, but I'm not sure I agree - anyway at 65mph I'm turning 3k rpms with TC locked (which everyone says is too high - that my tach is reading too high). One of these days I'll have to borrow a friends digital timing light and see what my true rpm's are.