First I must say that I'm still learning about cars/engine building... but everyone always says to make sure that your parts work well together and are matched up.

Well my question is what exactly should be matched? What parts? Does that mean they should be from the same company, like the Edelbrock Peformer package, or do you guys mean to keep the compression ratio constant..... Please explain... Which parts should be matched up and how do I match them.. (I'm planning on doing a rebuilt of my engine in Sept. and getting a custom built torque converter... but aside from that... what else?

Yeah I know I sound stupid but oh well. I know there's a lot of you on this board that know an aweful lot about cars. So I'd like to get input from a bunch of you.
Thanks!!!!!

 

It means that you should use parts designed to produce similar characteristics in the engine's operation. Very common mistakes are to take a stock low-performance motor and swap some of the easy-to-get-to or cheaper parts out for ones that are supposed to be higher performance, but leave other more critical ones untouched.

In most stock motors the single most important part that serves as a limit to performance is the heads. Stock heads do very well for stock things, but they are usually inadequate even for the ultimate potential of the rest of the engine. So, sticking a big carb or a racing cam in a motor with stock heads would be the classic mismatch situation. The cam determines what RPM range the engine is most efficient in; so if you get a racing cam designed to work best at high RPMS but have poor flowing heads, then what you get is not the best of each, but rather the worst. The finished product will have less low RPM torque than the original starting point because of the cam, but none of the high RPM power that the cam is supposed to deliver either because of the heads, and may actually go slower than it did when it was stock. Or, you may even get an engine all well-matched for high RPM power, but then have a rear end gear and torque converter that pins the engine into the sub-3000 RPM range all the time, so it really doesn't matter what the engine does at 6000 because the car will never allow it to go there.

Think of an engine as a pump. To make more high-RPM power, you do things to make it pump air & fuel through itself at high RPMs; hold the valves open longer, use bigger passages everywhere, etc. The engine's peak power output will occur at the RPM where the most stuff pumps through it. Now think of all those passages as a string of pieces of garden hose, all of them ¾" except for a couple of pieces of ½"; and imagine that you take one of the ¾" ones out and put in a piece of 2" hose. Will the system as a whole flow more? Of course not. If you are modifying an existing engine, the trick is to find the limits to the flow (the pieces of small hose) and increase them to the size you want. Usually the things you need to replace aren't all the romantic-looking sexy chrome gewgaws you see sticking through the hoods of professional race cars; mostly it's little things that you either can't see at all (cam) or don't look any different to the eye (heads) or seem like dead weight (exhaust).

400 RWHP requires 500 flywheel HP more or less. It's not a reasonable goal for a TPI 350, unless you're planning on adding a 200 HP nitrous kit. Work on getting 320 HP out of your L98; if you can get to that level, you'll be doing better than about 95% of the actually built engines that people out there have; and I'm not talking about people's "plans" or "dreams" or Desktop Dyno numbers, I'm talking real engines in real cars as they crank up and run.

 

There is no such thing as stupid questions. The cost of parts today it is best to know what works, There are many people who buy a bunch of parts only to be disapointed in the end. Hell I did that before NET came along. Keep asking what works or just copy what someone else has. I am planning on building a 383 and I have been told about 10 different things so far. Makes me wonder. Beware of master builders who have never built an engine, THEY READ HOT ROD

 

I'd like to build a 383 as well, from my L98. I'm trying to do as much research as I can abuot what to do and what parts to buy. (not just to make a 383 but to make my 350 kick some serious butt) I've got a nice chunk of money.. or I will by Sept. I'll have between 8-10 grand. I do need to spend 1400 or whatever on a rebuild of my tranny.. (pro built- I've heard good things) and might need to spend a bunch on beefing my rear end (9 inch?) and I would like to have a little left over for a good paint job... but the rest is gonna go towards my engine.

I can always get a ZZ4 and some other non CA-legal stuff and I can get it passed. But I'd rather not go that rought. I'd like to keep my L98 and my TPI and want to pass CA smog. I know it's hard.

My friend has an old Chevelle that supposedly has around 400HP but he get beat by his friend's new TA. He tells me it's because his parts are not matched correctly. I'd just like to make sure that I don't have that problem. What specific parts should be matched... what kind of combos... and why do you guys think that they make good combos.... no carb stuff.. (I want TPI).

If you guys had the money to spend... (I've been saving for a while) what would you spend it on in my boat?

I do plan on spending some on my suspension... Also... what would you recommend for that... other than SFC?

I know this is a lot to ask... but hey... I'm still learning.
Any help I can get would be great......

Thanks!!!

PS... Oh yeah.. the other thing I wanted to ask is about the 383. I was told that it would make my car fail smog. Not because of the looks but because of the sniffer. (The increase in displacement increased the hydrocarbon emission????) But I was also told that as long as I don't over do it on the cam , that I'll pass CA smog? What do you guys recommend?

I better post this before my computer f--k's up and it erased this mesasge.

 

Well, there isn't much more I can say than what RB touched on, but here's my experience. The motor I have has a horrible cam in it that stops making power past 3500rpms, and like an idiot I had 3:73s installed which don't match the powerband of the cam at all. Needless to say I went from 2:73s to 3:73 posi and didn't gain any time, that's why I got a cam swap planned soon.

 

You have to decide on a specific setup for your self, but it is good to do your research. I think if you tell us how much money you plan to have after you do the other stuff you plan on it will give more of an idea as to what kind of setup you should build(there are many different ways to get the same amount of power). How much power are you aiming for? One thing though is that it is hard to make a lot of power out of a tpi. I am not going to say go carb because I would rather have fuel injection also even though I am using a computer controlled carb for now. If you plan on building power out of a tpi motor be prepared to spend money. You will need after market runners deffinately. I would port the plenum and either port the base or get an after market one. I think that you have ran right into something people have a tough time doing with tpi which is matching parts. I think that a lot of this is because people want higher rpm power than the tpi wants to put out. You need to build it for a fairly conservitive rpm range. You could go super ram or mini-ram but these are also very expensive options. Im sure other people will have some other reccomendations. I would do some searches on the tpi board. Find people that have combos that work and ask them about there setups.

Ben

 

Ok... lets me more specific:

My goal is to have 400 HP at rear wheels. I want to keep TPI but I am willing to upgrade.... (I've got a 350 L98 - 91 Z28)

I'm gonna start with $10,000
but... -$1400 for Tranny
but... -$2000 for Rear end (??)
-----------------
and (taking the second derivative of the square root after carying the one).... uh...

$6600 left for engine/suspension

What would you do with the money?
(Oh, I'll be doing the install labor myself (w/ friends), except for building the long block and machining stuff and hot-tanking, magna fluxen - I want someone good to built my block)

... and a 383 would be nice... and so would actually passing CA smog
It's gotta be possible to go this fast and pass smog. I don't want nitrous.

Thanks for all the help!

 

I'll let more experienced people give you cam and head mods, but I would definately recommend the Hooker cat-back. Costs $200, performs great and sounds awesome, there's a sound clip in my signature.

 

hehe you need to quit talking about you hooker man

I hear about her all the time, can she really be THAT good?



though about matching parts

it would be like putting a cam with 240/240 and .550/.550 in your stock motor

you would have no power at all

to do that you need to get some good heads to match to flow of the cam

that is why some ppl will sell you a package that will include the carb/intake/cam/head all in one

that way the parts are matched to flow and work with each other