Originally posted by Lane at [You must be registered and logged in to see this link.]
Here's a list of basic recommendations for making a b-body faster.
The important thing to remember is that our cars are old and somewhat unique compared to the usual Camaro and Vette. Our cars are heavy and have an LT1.
With that in mind, talk to the guys here on the forum or a local B-body club who have the real experience about what works and does not. They're out there.
You just have to be willing to listen.
With a cold air induction system, valve springs, 1.6 roller rockers, headers, cat back, TC, gears and tune you can have a very good performing B-body. Heads & cam
and/or 383's are not required to have a fast & fun B-body.
Note that the list is not in a particular order except for the first 3.
1. First: Educate yourself about your LT1 engine: [You must be registered and logged in to see this link.]
and [You must be registered and logged in to see this link.]
2. Decide: Set a performance goal and budget and stick with it. Research and research more. Talk to local B-Body club members about your goals. Search this Forum.
Compare setups, engines, cams and heads here:http://www.top-et.com/impalass/
3. Tune up: Make sure all the basic tune up stuff is done and start with some "free" mods like the throttle body bypass. Here are two good sources for "basic" information about our cars, the LT1, maintenance and modifications: [You must be registered and logged in to see this link.]
and [You must be registered and logged in to see this link.]
4. Induction: Help your engine breath with a do it yourself "Home Depot" & "swiss cheese stock air box" system or spend the extra money for a nice RAISS system. Note that the performance gains are very small between the do it your self system and the high end RAISS. Here is a list of induction options: [You must be registered and logged in to see this link.]
5. Exhaust: Help your engine exhale with headers and cat back exhaust. List of header & exhaust options: [You must be registered and logged in to see this link.]
Tri-Y headers are a great performance mod for a stock and heads & cam 350. There are several "cat back" exhaust systems offered. Go with 2.5 inch diameter pipes for a stock to moderately modified LT1. A good budget exhaust option is to replace the stock mufflers with pipe
and leave the stock resonators on.
6. Valve springs and rockers:They will maximize your stock cam potential and give you higher RPM performance. There are a few after market valve spring kits but Comp Bee Hives seem to be the #1 choice. Go with a 1.6 roller rockers. Comp Pro Magnum self aligning 1.6 roller rockers are the #1 choice. Note that aftermarket cams require valve springs and roller rockers that maximize their lift. The cam manufacturer will specify the correct springs and rockers for their cam. See #9.
7. Torque converter: I would invest in a quality TC. Yank is a top choice by many. I do not recommend higher than a 3000 stall on a stock engine. With a 350 heads & cam, 355 and 383 engine you can go much higher than 3000. I recommend adding a HD fined trans cooler for the life of your TC and trans. Also, if you set in a lot of traffic, putting the trans in neutral helps.
8. Gears: For a street/track combo, go with 3.73 gears. They are fine on the street, highway and perform well at the track. When you do your gears it is a great opportunity to replace your stock Posi with a HD one from Torsen, Auburn or Eaton.
9. Heads: Ai [You must be registered and logged in to see this link.]
LE [You must be registered and logged in to see this link.]
and Mike Harris are some of your top choices for LT1 head porters. Dan Fahey is good a option for iron heads. Commercial "off the shelf" or "out of the box" heads can be expensive and not perform as well as having your stock heads worked over by a good porter. If you have money, you can purchase new heads from Trick Flo, Dart or AFR and have Ai, LE or Mike port them.
10. Cams: If you go with Ai or LE for your heads it is best to have them recommend a cam that will match the heads they built for you. For stock LT1 engines, the Crane 227 & GM 845 are great off the shelf cams. There are many other cam options, but with out a doubt the 845 & 227 have consistently proven to be performers for our cars. The GM LT4 Hot cam will need more stall and gears to be maximized. The GM LT4 Hot heads & cam kit was a great setup originally designed for Corvettes with 6 speeds. It was the only option for us a long time ago. There have been many better head & cam options offered since the LT4 Hot cam kit.
11. Strokers: This is where things can get very expensive IF you want this done correctly the first time. You do not want to cheap out here. Quality rotating assembly and heads & cam specified to take advantage of the extra cubes AND a quality LT1 engine builder are paramount to a successful build. Stock heads or some commercial "off the shelf" heads on top of a 383 will not maximize the potential of the stroker.
12. Engine Builder: "There are good parts and there are good motors, don't confuse the two." Mr. Mike Harris. If you can not do the engine build yourself, this is another area that is critical with going with experience and quality. The LT1 is different than a normal Chevy Small Block in some areas. You want a builder who knows the difference. My #1 recommendation is Karl Ellwein or Mike Harris. Check out Karl's list of quality builds: [You must be registered and logged in to see this link.]
If you decide to cut corners be prepared for poor performance and quality. You will spend more money in the long run because the engine you were in such a hurry to have now is slow and/or blows up. There are plenty of stories where builders have taken customer parts to build them a dream engine to only find out that all their parts they gave to the builder are not in their dream engine.
13. Programming: This is one of the most critical modifications. Not done correctly could cost you a engine and/or trans. You need an experience programmer who knows LT1s. I have used PCMForless. Other options are PCMPerformance & Ed Wright. The HyperTech programmer is only good for clearing CELs and gears & wheel size adjustments. Tuning with a 160 degree stat and CIA will make a stock car perform very well. Get a LT4 knock module for your PCM.
14. Intake, throttle body, fuel and MAF sensor. The stock intake is fine. If you go with heads & cam and a stroker have Ai or LE port your stock intake. Go with a 58 mm throttle body if you are going to add heads & cam. If you are not going with high performance heads & cam, a 52mm TB will do. The only MAF you need is an GM F-body one. You'll need larger injectors for built LT1s. 30lbs minimum. HD fuel pump. Check this out: [You must be registered and logged in to see this link.]
The stock fuel regulator is good.
15. Weight Reduction: Things to lighten the weight of our heavy cars: lite 15" wheels, headers, cat delete, tubular trans cross member, aluminum bumper supports, remove front sway bar and add a HD aluminum drive shaft. There are many other little things that add up like removal of the air pump system. You have to decide how far you want to go like living without AC.
16. Transmissions: 6 speed kits are available: [You must be registered and logged in to see this link.]
As for the stock trans, it's eventually going to give it up when you add more TQ because the 4L60E is not designed to handle much HP & TQ. When you go with your heads & cam or stroker be prepared to invest in a built 4L60E. There are other options, but I do not have any experience with different transmissions like the Turbo 350. Again, a proven experienced builder is a must. Check out CPT: [You must be registered and logged in to see this link.]
& ProBuilt: [You must be registered and logged in to see this link.]
For local options, ask B-body owners in your local clubs.
17. Brakes and suspension: Now that your ride is fast it would be wise to upgrade your brakes & suspension. Go here for your brakes: [You must be registered and logged in to see this link.]
Do the Proportioning and Metering bolt mods if you have 4 wheel disc brakes. Bilstein sport shocks are great if you want a firmer ride. Coil lowering springs can be a personal preference. Vogtland, Hotchkis and Eibach are good decisions. Do the lower body bushings. Some lower body bushings were not installed at the factory. Upgrade your rear lower control arms. Suspension options: [You must be registered and logged in to see this link.]
You can get "extended" rear control arms to center the rear wheels. Do not go with solid rear upper control arms. You risk cracking the frame at the upper CA mounting location because the solid arms do not flex and/or twist. For sway bars look at Hotchkis, BMR, HA and HO.
18. Hooking: With all of your new extra HP & TQ, you're going to need some drag radials or slicks to hook. I recommend going with slicks on some lightweight wheels.
Not only will this help your times, your back will thank you when you unload them from your trunk. Tracks require a drive shaft Safety Loop if you use slicks.
There are many other little things like electric water pumps and plugs. I am just providing basic recommendations. These are not the only choices and may not
be the best option for your goals.
There are many other ways to go faster. I did not cover power adders and nitrous because I do not have any experience with them. This thread is here to give
you a basic foundation to start with. PM the guys who have the #'s to back their advice. Go to local club meets. Join the clubs and race series like ECIRS.