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Proud new owner....questions abound


geodiggr
08-27-2005, 10:22 PM
Hi all,

Finally found what I've been looking for today...a 91 GMC Suburban at a decent, not great, price.

Anyway, the mechanic in me has a list of to do's and want to do's for the future...however I'm not sure where the informatin lies for these GMC's (been a Ford man all my life)...

Here's what I'm looking for if they exist...

A part's interchange manual/book
Shop Manuals
Wiring manuals (if separate from Shop Manual)
Tech tips on performance, tuning, and modifications

I've already located a Fuel Injection book to buy...

Any other suggestions for a smooth running, fuel efficient (as much as possible - this is a weekend only vehicle), and enhancements would be greatly appreciated.

Thanks,
Rick

Ryan685
08-28-2005, 12:52 AM
Hello Rick. I've had a few parts/interchange manuals for different vehicles. I came across them at an auction. These aren't something just anyone can get. You can usually call a salvage yard and ask instead of buying an expensive interchange manual.

Shop manuals. They are nice to have but again, some service manuals can run in the hundreds, like Motors Manuals. Most liberarys stock Motors Manuals. You can check them out for $20.00 deposit wich they return when you check it back in. Or watch eBay for them.

Wiring manuals. Again that's part of Motors Manuals.

Finding performance info on chevrolet engines is kind of an odd question. People have been hot-rodding these engines since the dawn of man. If it's really a serious question I'll behave. First off, the 350 chevy engine being the Worlds most popular engine, everyone makes parts for it. Search "Summit Racing" or "JEGs" or google search for whatever it is you are looking for. EBay has some great deals. You can limit the search radious on eBay to around your zip code. The '91 engine computer has replacable chips. Some require 91 octain fuel to work correctly.

Where and how you drive has a lot to do with economy. Mechanically I like 3:42 rear end gearing for the highway. Yours may be a 3:73 which is lower geared. They do well towing. On engine performance. I like the Vortec engine, mostluy because I couldn't afford to pay cash for a 2000 and up model with the LS (I think) series engines. If you aren't into engine swapping, intakes, headers, superchargers, aluminum heads, roller cams, turbo's and a million other internal or bolt-on parts are out there. Everyone has their own recipie for building a small block. Ford now-days has just as much for their engines & transmissions as chevrolet does. Personally I would keep a Suburban quiet. A few trucks in my neighborhood have the "no muffler" sound and it sucks to hear them go by every day. I wish them the worce headache out on the highway from the droaning inside the cab. No one likes to hear a blatting exhaust from a stock engine. I love the sound of a healthy high compression engine with a good cam. Loud doesn't mean fast, wish more people understood that. Reasonably, you are building an engine to pull a 6000lb vehicle. That means bottom-end power or torque is what you want. Long intake runners work best for torque. The Vortec heads have 64cc combustion chambers and work really well for making a lot of torque. You can swap Vortec heads on your engine but will need a Vortec intake, either factory or aftermarket. Your best bet is to read. Spend some quality time searching google for forums discussing whatever area of info it is you seek. Try & stick with the truck crowd though as car engines are tuned differently.

Hope some of my ramblings are helpfull. Take care.

Ryan

geodiggr
08-30-2005, 11:22 PM
Thanks Ryan,

I've been a Ford Truck guy up to this point and I've found a good amount of the material (manuals) that I was asking about for decent prices...hence my question. So, I'm a little out of my element with the Chevrolet's and "newer" technology.

I will keep your advice in mind about the parts interchanges and I'm sure I'll pick up pretty quick which components will swap out. I'll definitely look for the Shop Manuals at the library and acquire them if the funds allow it.

I guess on the performance part I'm just looking for tech-tips and things to do for performance, economy, and problem solving. I will browse the internet and hopefully find a few more places like this to kick around some questions.

Your last paragraph is exactly the type of information that I'm looking for. I agree with you and I'm just looking to put together an engine that will work well, i.e. have some torque, and the best possible fuel economy on long trips. There's Flo-Masters on the truck already so I won't change them...but I'm a stock kinda guy otherwise. I will start my searching and learning...and I'll try my best to put that Ford stuff out of my head...LOL But, I'm looking to rebuild this truck's entire drivetrain as time and money allows. Not because it needs it, but because I want to learn and love roaming the junkyards and tinkering.

I appreciate your post.

Thanks,
Rick

Ryan685
08-31-2005, 03:10 AM
Thanks Rick.
I have had a few camshafts made for for me by lunati that worked really well. These were solid lifter cams for a 355ci in the 500hp pump gas range. This was before Vortec heads came out. I was restricted to factory cast iron heads with small combustion chambers. Compression ratio figures into the formula. Not enough compression and the cam doesn't work. The engine had 11.3:1 compression with .546 intake lift with .560 exhaust lift. Lobe separation was 110 degrees and 1.5 (stock) rocker arms, although they were Crower stainless steel roller with 7/16 studs. For a street engine you must use no more then 120lb of valve seat pressure. Anyway what this all means is, lift is torque. Duration is horsepower. What I was going after was 500ft lbs of torque @4500rpm. It was very close. The engine ran on a engine dyno for several pulls and that was all. It had a lot of secret tricks I've learned over the years. Today I would build it differently because cylinder heads have improved of course. Back then the rules has us limited to spending $5000.00 and no aluminum heads or roller cams. I had what's called a "mushroom lifter" cam but it wasn't legal for the contest. We were allowed to do some porting to the heads and use plates for adapting headers, which allows some cheating because you can raise the exhaust ports some. Never lower exhaust ports, even to correct mismatch, just leave it. Chevy heads lack in the exhaust port compaired to most other makes. Ford heads excell on a flow bench but, the cranks have a bad connecting rod angle. Internal parts working against each other. This was in the 355ci engines, not the 302's. Above 500hp chevy engines will begin to pull the main webs out of the block. They should have run the sides of the block all the way down to add strength to the main caps. They knew this way back in 1965, that's why the big-blocks entered the scene. Small blocks are fun to build, lots of good information is out there. Fuel management has come a long ways compaired to what I did a few years ago. I'm not sure what the fuel consumption was. When testing an engine on a dyno, it measures how much air and fuel the engine is using during the pull. Today I would pay more attension to that. Some of the ignitions used today are really good. I was using a total of 36 degrees of timing all-in at 2600rpm. That works really well for pump gas, which we all had to use the same fuel. Some guys said go ahead an let 'er detonate and basically ruined their engines. I sold mine to a friend and it's still around today. I think it would have worked pretty well in a 6000lb truck. 500+ horsepower at the flywheel results to about 450hp at the rear wheels. 486ft lbs of torque at 4500rpm would move a Suburban down the road. A 454 would take a few seconds to get around it haha but he'd think you had a big block under the hood as well. Heat, as always would be an issue. Stressing a 350 like that for several years...it wouldn't stand up as well as a 454 would. Well, gas is suppose to hit $3.00 a gallon tomorrow. I topped everything off and filled up the gas jugs. Time to wheel the Kawasaki out and ride it until the oil men feel better. Around here their ramming alcohol gas down our thoats again. Reading all the newspaper adds, it's close to pouring heaven in your tank. Gasahol is bad news. Even though it's suppose to only be 10%, those that run alcohol in thier race cars know it eats everything. Nothing is alcohol proof. Rules require replacing fuel cells and entire systems anually. Back when they first tried gasahol, carburetor gaskets, seals, diaphragms etc deteriorated. Fuel filters clogged up because alcohol cleans everything up really well as it eats it up. I guess the good news will be, that tank you replaced will look like new inside. Expect to feed your car a lot more parts, like fuel filters, pumps, line, injectors. I at least figured to read some of the local racers comment in the paper about what a bad idea it was last time. I guess that whole generation "forgot" everything they went through. For those that don't know. You need TWICE the amount of alcohol compaired to gasoline. So you are getting 5% less gas per gallon. Your engine is going to run richer and use MORE not less gas because the sensors are not going to be fooled. The computer reads the 02 sensor, it says lean, so the injectors spray longer to compensate for the leaner fuel. Remember, when running alcohol, jet sizes are twice the size of gasoline jets. That's never been a question in the race car World. Neither has gelling in cold. Alcohol will gell in cold. It doesn't clean out very well either, like in replace everything kind of gell. 10% won't cause gelling and they are suppose to stop adding alcohol in the winter months although none of the information I've read this go-round states they are going to use common sence.

nosefirst
09-02-2005, 10:32 PM
Go to www.paceparts.com and enter this parts #...12558060sh

and check out this #spe11011

Ryan685
09-03-2005, 01:23 AM
Nosefirst, have you tried the spacer? More plenum area should improve torque. I'm tempted to purchace one. Their dyno chart starts out kind of high (3000rpm). The heads are a steal, better then bowtie heads they state, I agree.
Rick, I finaly had a reason to get into the gas peddle today with the Vortec. Damn impressive!!!! Got around the blocker vehicle pretty quick and made the exit ramp. I really didn't expect my truck to get up that fast. You must do the Vortec heads, or the whole engine swap. I'm sure the roller cam has a play in how it makes torque like this. At $3.30 a gallon, it's back to idling around again... sure was fun mashing the peddle though, you had to be there.....

nosefirst
09-03-2005, 08:33 AM
I have not, but I'm thinking about doing the heads and the spacer when I fix my intake manifold gasket. I'm also thinking about converting to a marine intake at the same time.

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