I took a chevy 350 out of a '88 full size blazer. The block was purchased in '98 from Cloverland motors. The blazer had 66,666 miles when the motor was put in. I took it out at 89,000 miles. So the motor doesnt have alot of miles. When I pulled it The motor was fuel injected. I put differant heads on it. I have a Weiand performance intake, Iv got a Holly double pumper, Flowtech afterburner headers, and dual Flowmaster pipes strait out the back. Now I know to some of you thats not alot. But I drove the blazer before I took the motor, and It feels like it doesnt have the power it should for everything Iv done to it. When it was in the blazer it had alot of power. Now it feels almost the same. Any ideas?  

i would check your cam,head,intake,header and carb combination to make sure they all work together for best performance.  

You did'nt say what heads you switched to or carb cfm. You could have made it worse than better. Without other important modifications,  the only improvement you may notice would be from the headers.  

Im not really sure what heads they are. I bought them from a guy who used to work for me. His dad built modified race cars. Then he would race them. He was a pretty good mechanic, so I just assumed he was givin me something good. And the cam is stock. Thank you for the feedback Im kinda new at this.  

Whats the carb cfm? Vaccum secondary models will almost always prove advantagious over a double-pumper unless the vehicle is light. Why did you change the heads?  

The Holley carb is 600 cfm vaccum secondary. I changed the haeds because it was fuel injected so the 4 center bolts on the intake are at a differant angle. So I had to change the heads. In your answer you make it sound like a vac sec isnt a double pumper. Is this true? All the paper work and box say it is. Another thing, off the line it will hesitate. If im already movin and hit the kickdown, Boy does she move. 1 more thing I heard that you lose something like 40% of your power through your tranny. How much of this is true? Oh yeah and the vehicle is heavy, '81 Buick park ave, 4 door. Not your average street rod. But its clean. I am looking for something differant.  

I would also look to the distributor what is it hei or points if the spark cant keep up you will get hesitation, same for timing make sure it is right for the motor. I would also try finding out what heads those are.  

The Holley 600cfm vac. secondary is a good choice for your setup. Double-pumper employs two accelerator pumps(hence the name, Double-pumper). One for the primary, another for the secondary. Vac. secondary carbs. do not use the second accelerator pump. A lot of people confuse dual-feed with being a double-pumper. All double-pumpers are daul-feed, also many vac. secondary carbs are dual feed. Your 600 should be a single feed with a small tube from the inlet casting, going back to the secondary bowl. Now, down to buisness. Your stumble sounds like the accelerator pump out of adjustment. Adj. as follows. With carb in idle position adj. pump arm so it just touches the pump diaphram. No up-down movement, just slight tension side-side. That adj. will make your pump react instantly with throttle movement. Your disapointment in performance may be the tall gears that car most likely has(3.08 or taller).Set initial timing 8deg. and go from there. Also I want to say, anytime you adj. idle speed, you must re-adjust accelerator pump. Hope this helps.  

Man I really appreciate all your suggestions. How would I go about finding what heads they are? And the Dis is HEI. was thinking of getting a better one with an external high voltage coil. what do you think? I know this may sound stupid but 8deg before or after? And the  tall gears would be in the rear end?  

A fancy distributor in your case is probably a waste of money. GM parts interchange book or a How-to Hot rod book would tell you everything you need to know about your equipment. That's 8deg. BTDC, and that's a ballpark figure to get you in the game. You may find it runs better at a different setting. The tall gears are in the rear end. If you want to pursue better performance, you could swap out the gears for more suitable one.  You can find the rear-end ratio yourself by jacking up the back of the car, and counting how many times the driveshaft spins for one revolution of the tire. That car would need 3.73 ratio to get the performance your looking for, which is close to what the Blazer had. What engine was original to the car? Sounds like you could have a hell of a sleeper if you get things in order. Feel free to ask questions, I will do my best to help.  JW.  

Thank you very much. You have been a big help. The original engine was the v6 252. A real piece of crap.  

Wow that s pretty small POS v6 engine.  

Your tellin me. I drove it. I marked the bottom of the tire and the drive shaft spun the tire 1 rotation the drive shaft spun 1.5 times.