350 CHEV questions

Sneakymedic

Sneakymedic

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So if one was to buy a older model truck with a 350 in it and wanted to change the 2 Barrel out to a 4 Barrel for a little more umph, is that a difficult process? Is there much more to it other than changing out the intake and carburetor?
I see a lot of people refer to the 350 and SBC after it, is this reference small block Chevrolet?
 
The carb and intake is straightforward. Sometime the throttle linkage and brackets can be a pita depending on the setup.
 
A couple of caveats from my experience on a Ford 351...

Check with some Web sites that have info on that same motor. You might gather some good information from someone who did that same swap. Bypassing a lot of learning curve and getting a starting point.

Be sure the new carb is the same or 10% higher (my preference) CFM than the original.

Not all 350's are the same (valves, cams, etc). Most of the aftermarket carbs are universal and might not be perfect for your engine. Be prepared to tune the new carb: rejet, change metering plates, power valves.
 
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More fuel doesnt always mean more umph.
remember 14:1 air fuel ratio ( this is the magical numbers with pump gas) If you dump more fuel, you need to dump more air. The only "real" way to do that is with cam lobe lift and duration. The piston traveling downward is the vacuum sucking in the air (with intake valve opened)
 
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I suggest taking a hard look at stand alone EFI systems such as the Holley Sniper. Summit has a house brand one too. Not a whole lot more for essentially no tuning, easy starts, better fuel economy, throttle response, basically everything. Unless I had a carb sitting there, made more power than an off the shelf system could support, or competed in a race class that required one, no way I'd use one.
 
Mike Overlay said:
More fuel doesnt always mean more umph.
remember 14:1 air fuel ratio ( this is the magical numbers with pump gas) If you dump more fuel, you need to dump more air. The only "real" way to do that is with cam lobe lift and duration. The piston traveling downward is the vacuum sucking in the air (with intake valve opened)
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This is dumb. You meant to tell me I can't just buy a RMR for my Grock and I instantly shoot better?? ??

But yes, I figured I'd replace the exhaust and some headers, etc... To "match it up" if you will.

Probably end up with a supercharger. Screw @amnesia and his vette. Lookout for the farm truck!lolol
 
Beef15 said:
I suggest taking a hard look at stand alone EFI systems such as the Holley Sniper. Summit has a house brand one too. Not a whole lot more for essentially no tuning, easy starts, better fuel economy, throttle response, basically everything. Unless I had a carb sitting there, made more power than an off the shelf system could support, or competed in a race class that required one, no way I'd use one.
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I see I'll owe you more hay. Lmao.
 
Beef15 said:
He gave you the roadmap right there, LS + hairdryer, that's all the racer and bench racers at work ever say, strangely none of them have it though.
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I reallllllllly wanted to go the NA cammed LT1 route because that chop is like music to my ears. The bad part is it was pretty expensive and less gains than the above system. I said I won't build it out anymore but lets see what happens after the kit/headers and possibly meth goes on. Anything after that needs pistons/bigger & better tires. At that point I'd just find my way into a z06. This is my way of having stock z06 power for 20k less.
 
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Mike Overlay said:
Stock 350, low compression heads, small valve motor?
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It is a 350....and stock with 62k on it. Bout all I know about it Picking it up next week. I'm not trying to make a race truck outta it, but just a neat cruiser
 
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Sneakymedic said:
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It is a 350....and stock with 62k on it. Bout all I know about it Picking it up next week. I'm not trying to make a race truck outta it, but just a neat cruiser
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Alrighty then, pick up a mild cam kit. Edelbrock intake kit. A decent set of hooker headers and 2 inch exhaust, put in a 3 row radiator and be done with it. Good acceleration, mild power to play with and a good cam lope sound while easing thru the parking lots. You doing the work, less than a $1000.

And if you really want to screw with folks, use a Pete Jackson "noisey" gear drive
 
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62k on the clock is pretty amazing. I agree with Mike. Mild cam headers & exhaust should fix it up nicely.
 
@Sneakymedic Be careful not to go out and buy a post 1985 intake manifold. The bolt hole angles are different than the pre 1986 350s.
 
amnesia said:
I reallllllllly wanted to go the NA cammed LT1 route because that chop is like music to my ears. The bad part is it was pretty expensive and less gains than the above system. I said I won't build it out anymore but lets see what happens after the kit/headers and possibly meth goes on. Anything after that needs pistons/bigger & better tires. At that point I'd just find my way into a z06. This is my way of having stock z06 power for 20k less.
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LT1...bruh...those motors are the damn devil
 
So I've never done much breaking down of any motors or anything like that. What benefit does one get from putting a set of LS1 heads on the motor that I have?

I know on the pulling tractors people talk about domed pistons and increasing compression which I assume would increase torque. I've been watching some YouTube videos on porting and polishing on the head as well. Honestly I don't have the skill set or the tools and space to be able to pull a motor and do a lot of work to one.
 
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Heads is everything, so to speak. A good bottom end is useless without a decent set of heads. A decent set of heads are wasted on a mediocre bottom end.

On that motor, its not worth the trouble for a set of heads. Much less worry about the benefits of a port and polish.
 
Step one buy a Windsor. Step two Stroke it to 408. Step three buy the biggest ARF/GTX/trick flow heads. Step four mild cam. Step 5 blower, step 6 long tubes. Step 7 rock crushing, heartbreaker, wheelies.
I'm a ford man and can't help with these chevy problems.
 
If go the route Mike Overlay suggested above, which is the way to go imo, I'd put a fresh set of valve seals in the cylinder heads. With only 62k miles on a vehicle that age, the valve seals could be brittle.
 
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Putting LS heads on a SBC isn't practical. Mike has given very good advice.

The most important part of any build is to establish a budget, then evaluate your options within that budget.
 
John said:
The most important part of any build is to establish a budget, then evaluate your options within that budget.
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A $100 a horse is a realistic starting point if starting from scratch.
 
yeah, Im all about the Summit set up he suggested. I cant do it myself, but it is a one stop shop, sort of. That is the route I am taking with it. I was just asking questions, since you guys are pretty smart about all things engine.
 
So I got it home tonight. Did some searching around on it. In 1999,it had 32,000 on it. One owner really. I actually drove it home. Ran pretty good to have no shocks and four dry rotted tires. Whew. It has front disc's, which is important when I get to the drop spindles. And on further inspection it had a factory 4bbl on it. So I decided not to do too much with it since I couldn't hold it in the road :) I did find a new motor for it. Mind you... This monster is on essentially a lawnmower size pulling " tractor"
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You will notice a significant difference in just changing the intake and carb. The only thing you'll have to really pay attention to, is what direction your rotor button is pointing in before you pull the distributor. The distributor on a chevy runs through the intake, is driven by the cam, and drives the oil pump. When you slide it back in, just be sure the rotor button is pointing in the same general direction. The split pin in the bottom will only allow it to fall in either in the right place or 180deg off. It will usually advance just a little so you have to play with your timing just a bit... it is not complicated but may sound that way... pay attention to keep your gaskets aligned properly. 1st one I did at age 17, I ended up having to do over. Had coolant getting in one of the cylinders.... any trouble, and you can call me. I can walk you through it....... LOVE THE TRUCK
 
amnesia said:
I reallllllllly wanted to go the NA cammed LT1 route because that chop is like music to my ears. The bad part is it was pretty expensive and less gains than the above system. I said I won't build it out anymore but lets see what happens after the kit/headers and possibly meth goes on. Anything after that needs pistons/bigger & better tires. At that point I'd just find my way into a z06. This is my way of having stock z06 power for 20k less.
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I have an 04 NA goat that would love to sniff on that vette
 
So, tell me about distributor/coil set up vs an MSD distributor set up. I guess I can youtube it, but that doesn't give me an "experianced" pro vs con discussion.
 
I'm kind of surprised no one has mentioned it, but make sure you pay close attention to the throttle valve (kick-down) cable set up. If you get that wrong, your transmission is not long for this world. Assuming it's an automatic.
 
Sneakymedic said:
So, tell me about distributor/coil set up vs an MSD distributor set up. I guess I can youtube it, but that doesn't give me an "experianced" pro vs con discussion.
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The MSD has some advantages for certain applications. For what you're doing a stock style HEI coil on cap distributor is fine. They are reliable up to 6500 RPM easily, which is all you are likely to see before the valves start to float.
 
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