engine suggestions for high altitude?

[Wyomingboy]

Just got a 90 Blazer with a 350 tbi and after driving it about 2000 miles (it has @80k total miles) put on headers, de cat'd it and Edelbrock muffler on it. It's still pretty disappointing in the engine department. Here at 5200 feet elevation it has to shift frequently, with the auto for small grades and such. Do any of you have experience with the 383 towing motors built by CNC machine in Brookings, South Dakota? That's what I'm leaning towards, since I don't have time, place & tools to build up a motor.

Thanks

 

[buefchris]

Never delt with BROOKINGS but I have a 95' w/ a tbi 350, good motor but,gutless as all hell. Have heard that a 383 w/ a EDELBROCK muliport conversion really wakes um' up.

 

[Wyomingboy]

yeah I was thinking about the Edelbrock multi port, but Edelbrock has not been very helpful explaining how to make their multiport system work with the 383.

I was actually wanting to get a GM Performance parts HT383, but the guy at the dealership told me it wouldn't work with the TBI.

The people at CNC Motorsports told me their engine is very similar to the GM HT383, but it will work with the stock computer & TBI system, with modifications they recommend. So I'm kind of leaning that way. I was just wondering if any members had experience with these people?

 

[bigblock72]

The HT383 is a great motor that will work fine with the TBI, of course it will need a chip burned to work with it. You'll also need a different intake to bolt to the vortec heads. I've been burned so many times by rebuilders that I just stay with crate motors, almost zero warranty issues.

 

[4X4HIGH]

The biggest thing to watch out for is that it has the correct MAP sensor for the elevation. There are different sensors for different elevations. I guess what i'm saying is that GM did not use just one MAP sensor for every TBI vehicle. Depending on what part of the country the vehicle was shipped to originally had a bearing on which MAP sensor the vehicle has installed on it.

 

[Wyomingboy]

Hey thanks guys. I called Scoggins & Dicky about an HT383 and the tech line guy is the one who told me the motor would not work with TBI and he had no suggestions about how to make it work ? So I kind of dropped it from that angle and started looking for another motor vendor and type of motor. But I agree I don't want to use a rebuilder and I am going to get a crate motor, just wondering which is the best application ?

 

[GRINCH]

You never did say what you are running for Gears or Tire size. Even 33's with stock gears will make a 350 seam sluggish.

I live at 5000' and run a 96 Vortec Motor with Edlebrocks MPFI and am very happy with it. I have 37" tires and 4:10 gears. It's a 90 K5 and Edlebrock burned the chip.

 

[Wyomingboy]

My 90 chevy is totally stock with stock gears, 3:73 I believe with 10.5x30.5 tires. I have put in new plugs, wires & Jacobs electric spark booster, O2 sensor plus opened up the exhaust.

 

[gnihcraes]

My old 85 Crew Cab K35 with 350 and 4.10's does reasonably well for lack of power and lots of weight... at 5000 ft and up... (stock tire size)... A friend has a 90's suburban with 350 TBI Auto and it doesn't do as well, it's got higher gear ratio (3.73) I think...