[Pre-StrokerC1500]

I'm about to rebuild the engine in my "restored" '91 Chev C1500 and I have a few questions. I have some decent mechanical knowledge but this will be my first engine build.

The truck: Daily driver with a stock TBI 350 and a 700R4 transmission; It's lacking some power so while I'm at the early planning stages I was debating on converting it to a 383. The only mods done are an exhaust system, intake, Hypertech chip and a TBI spacer.

I don't drive too far for work, so I'm not too concerned about MPG, but I was wondering if anyone knew about what to expect? I currently get 15 MPG.

Will the stock TBI system work with this change? TBI upgrade? Chip?

Will I need to look into changing the torque converter? Suggestions?

What exactly is a vortec head? I'm under the impression that it is still cast iron but the valves are bigger and a new intake and exhaust manifolds are needed.

Last question (for now). Potentially the most important question, do you think this would pass emissions?

Thanks in advance; I just found this forum and I've been stuck in front of the screen for about 4 hours now. Great site!

[32Tudor]

I just built a 383 and feel like I survived a plain crash!

I can't answer the MPG question, but fuel injection is your best bet if you have any concerns.

Here is my summary list;
1. Cap screw rods. I didn't and ended up grinding about 1 gram off the top corner of the rod bolt and rod shoulder to clearance a .447 lift cam.
2. Roller lifters. Read the article about cam life, oils, lifters in the current Hot Rod magazine. It sounds like roller lifters avoids a lot of expensive problems.
3. Patience. Assemble withOUT rings, clearance check EVERYTHING. The side of the block along the oil pan seal, the rods near the cam (especially #2 and #6), the oil sump, the pan itself.

I think mine will live. I drove it to work again today (third time) to see if all is well before I set off to FL for the power tour in a week and 4 days.

If all you want is more torque, I would go with a 350 and the right cam selection. Advance the cam 4-6 degrees (for bringing the power range into the lower RPM range), and get a 700-R4 trans (good high (numerically) first gear). My 70 Chevelle Wagon would leave the line better than most cars because of the 3.08 first gear.

[Pre-StrokerC1500]

Thanks for the reply. I don't really tow anything except for a very small utility trailer (occasionally) so I'm not looking for a boat-load more torque, just some. I'm hoping to rebuild the transmission at the same time I pull the engine, but maybe I should wait incase I want to change gears.

Are you using a TBI setup or MFI?

I haven't pulled it apart yet, but I think GM used roller lifters in this block. That's something else I need to look into, but either way, they're getting replaced.

[firestone]

I dont know a whole lot about the tbi setups, but the Vortec heads are great. They have slightly raised intake runners which allow them to flow very well even in a stock casting. I have a fried that just put some vortec heads no a tbi motor and he said that it makes way more power and actually gets better gas mileage.

Adam

[Pre-StrokerC1500]

No kidding? This may be a dumb question, but are Vortec heads the same heads that are on the newer trucks with the Vortec engines?

[Mustangsaly]

Originally Posted by Pre-StrokerC1500

I'm about to rebuild the engine in my "restored" '91 Chev C1500 and I have a few questions. I have some decent mechanical knowledge but this will be my first engine build.

The truck: Daily driver with a stock TBI 350 and a 700R4 transmission; It's lacking some power so while I'm at the early planning stages I was debating on converting it to a 383. The only mods done are an exhaust system, intake, Hypertech chip and a TBI spacer.

I don't drive too far for work, so I'm not too concerned about MPG, but I was wondering if anyone knew about what to expect? I currently get 15 MPG.

Will the stock TBI system work with this change? TBI upgrade? Chip?

Will I need to look into changing the torque converter? Suggestions?

What exactly is a vortec head? I'm under the impression that it is still cast iron but the valves are bigger and a new intake and exhaust manifolds are needed.

Last question (for now). Potentially the most important question, do you think this would pass emissions?

Thanks in advance; I just found this forum and I've been stuck in front of the screen for about 4 hours now. Great site!

I have the same questions about a 87 suburban 350 tbi engine, (I'm lookin 4 more HP & TQ) my motor is hanging on my motor stand now. if i build a mild 383 with a touch more compression & cam, plus headers and 2 1/4 dual exhaust, will my computer still be happy ? or can I make it happy ? what heads would make this work out and be the happiest ? and would it pass emissions?

if i build the original 350 with a touch more compression & cam, plus headers and 2 1/4 dual exhaust, will my computer still be happy ? or can I make it happy ? what heads would make this work out and be the happiest ?




Mustangsaly

[32Tudor]

I may not be the best source of this info, but I have a 93 LT1 in my 32 Ford and it runs like a raped ape. Tons of pull at low and high RPM.

Roller lifters. As long as your old ones arn't damaged by a catostrophic oil failure, they are still good. You don't have to replace them like we used to with flat tappet lifters. Plus you will find that they are very expensive.

On my 383, I am running an Edelbrock 750CFM carb with an Edelbrock RPM performer intake. I used World S/R Torquer heads (67cc) and flat top pistons, for a net CR of 10.5:1. I used a 222/222 .447 lift cam (the traditional 350HP cam). It runs pretty good.

One thing that I see people do all the time is use components that increase HP at in the high RPM range. Big pipes, headers, big cams, big carbs (I know I have one too), all add to your top end HP. Think about how you are planning to use it and ask yourself if when you are winding it out about even 4000 RPM, you say, "I wish I had more HP". I usually find myself saying that at the low end, when I would mind breaking the tires loose or roosting from 0-55MPH, pinning your friend back in his/her seat and looking good doing it.

In first gear, by the time I am up above 4000RPM, I am getting ready to shift into the next gear.

If you want to drag race, you might want that top end HP.

The TBI and and TPI are nice, but you start taking about more money and some learning curve on computers. There is tons of info out there about fuel injection, and this is a good time for a plug for a guy that really helped me out a lot. Jim at Jims performance http://www.jimsperformance.com/. He sold me a fuel system and reburnt my chip, but better than that, he was extremely helpful with some error codes and a fuel pump that I siezed (on debrit).

[Pre-StrokerC1500]

I'll have to check him out because I will probably need a chip.

This engine has 180K miles on it, but it's still in awesome condition; runs like a top. Do you still think I should hang onto the OEM rollers?

You're right about the HP vs TQ theory. I'm not planning on driving at 90+ mph often, so it would be much more beneficial to just get up to 60-70 faster. However, I don't want to wind it out like an old diesel would.

I have an OEM TBI, so I imagine that will need to be upgraded. No headers yet, but everything behind the manifolds is 3".

[Mustangsaly]

on my 87 suburban 350 tbi engine, (that I'm lookin 4 more HP & TQ) my motor is hanging on my motor stand now. if i build a mild 383 with a touch more compression & cam, plus headers and 2 1/4 dual exhaust, will my computer still be happy ? or can I make it happy ? what heads would make this work out and be the happiest ? and would it pass emissions ?






Mustangsaly

[Pre-StrokerC1500]

I have no idea. Maybe someone else can answer.