El Camino Central Forum banner

Headers/Dual exhaust conversion

6K views 27 replies 10 participants last post by  JJLT1 
#1 ·
#2 ·
Looks just like the G-Force unit I bought, works well but they are a bit "fiddly" to install. Maybe if you have access to a lift it won't be so bad. Not a bad price. :gmorning:
 
#3 ·
dual exhaust is a good idea, but
headers and holleys are for racecars..

to get the driver side pipe to tuck up better then yes, something needs to change..

if you use Hooker long tube headers? the driver side header hangs lower so the crossmember is not
absolutely necessary but you loose some ground clearance..

if you can weld, or know someone, you could mod your crossmember,
or just build one..

130$ Jegs free shippin
http://www.jegs.com/p/JEGS-Performa...dy-Transmission-Crossmembers/3150980/10002/-1
or
175$ Iceman, check shippin price
http://www.gbodyparts.com/product_i...=1152&osCsid=1cbbd88cddd46fb3c4cc49d988b39556

:texas:
 
#4 ·
dual exhaust is a good idea, but
headers and holleys are for racecars..

Yeah, this won't be a race car by any stretch, but I want better than stock performance. So, I am considering either a number of mods (headers, dual exhaust, cat delete, cam, heads, intake, carb) on my 305 with 116,000 miles, or a new crate 350 swap.

I know the 350 swap will be more expensive, and either way I'll be doing a number of things I never have before. My mechanic tells me it's possible to do all the mods with the engine in place, even the cam if the radiator is out and front brace removed.
 
#5 ·
By federal law if the car came with a catalytic converter, it needs one forever. If there any emissions testing in your area, it will not pass. The exhaust will stink more with no cat but that is no big deal. It is a law that is widely ignored in may states, but it is a federal offense to remove the Cat.

Most street cars run best whit a X pipe in the system. Droning can be a problem. It all comes down to what your goals are for the car.
 
#6 ·
My county in NC doesn't require emissions testing on '96 and older (currently), so my inspection station has told me they don't check for cats; however I'm not opposed to them. New ones will flow much better than the old ones certainly.

About the X pipe, I've seen those systems for sale also, but didn't know what the advantage was. Cuts down on drone? Still requires the new cutout crossmember I guess, because it's still 2 pipes after the X.
 
#8 ·
IMO
depending on the setup?? type and pipe diameter/length, muffler/flow/back pressure, routing/install,,
90% of the power increase will be from the dual exhaust, the other 10% average hp is not
worth the aggravation of headers- the install, ground clearance, burnt wires, plug access, leaks,
on a stockish motor..

and after all that youll still need to change the rear gears for the real potential to be known..
i'd do the duals without the header cost, and rear end gears and then see what you think about it..
gears will cost more than the headers, but show bigger returns..
if you want more??
if your thinking heads, cam, intake,
keep driving the 305 and find a roller cam 350 or 383 to buy or build, less down time just to swap..
up-grade money spent on a 350 or 383 would show bigger returns than on the 305,
same money for more torque/power..

:texas:
 
#10 ·
Do you still have the computer & the carb & distributor ? If you toss the computer, and replace the carb & distributor, cruise wont work if you have it..
IIRC, There is a work around for this that I've read about on these great forums......it's got something to do with the black wire (for the cruise, under the dash) coming from the ECM needing to be grounded.
 
#14 ·
I spent my time last night browsing Jegs and Summit exactly for that; think I'm headed in that direction. Blueprint engines are cheaper than GM, but there may be a good reason why... anyone have experience there?
 
#17 ·
#16 ·
Blueprints motors are rebuilt , I looked at them before deciding on the GM 350/290 crate motor . I kept my stock Carb and computer .I just installed Pypes sgg53s exhaust . its a cat back dual 2.5 stainless steel with street pro mufflers .
here's video of idle ,
https://youtu.be/mNgEJS1DS0s
 
#21 ·
To delete the CC carb, you will also need to replace the CC distributor....and if I'm not mistaken, you will need a new coil / ignition system. You can do a search in these forums and find a lot of these answers (top center of the page under the NECOA banner)......Also g-body forums / g-body central / malibu racing / g-body.org are somewhat helpful.

You can buy headers that have SMOG pump ports in them.....I've seen them but I cannot remember where. But I did find this with a quick internet search. http://www.hedman.com/Hedman-Smog-Pump-Kits
 
#22 ·
I had issues getting my 350/290 to idle correctly . It only makes 16HG of vacuum when the stock 305 makes 25-28 HG . This was throwing the MAP sensor out of whack and sending the wrong signal to the computer leaning out the mixture via the mixture control solenoid . My final fix was moving the MAP sensor Vacuum hose to the Intake (larger diameter hose ) and adjusting my idle mixture screws out as much as possible . I am in California so I am stuck with the Smog stuff . I read up recently about drilling out the Idle mixture holes a little . I have an extra carb so I might try that as my idle RPMs are still a little low .
 
#23 ·
JJLT1, I've also noticed that cross members which fit 200R4 are a bit more expensive than those for 700R4's.

David, I have gone back and forth about whether to buy a crate vs doing the rebuild myself, mainly because I enjoy putting things together. If you have a good core and crank, any reputable machine shop will do the necessary work and place you on the right track. However, due to economy of scale in purchasing parts, these online sources are very tempting. Rather than rebuilding the 305, I would go with the 350. These blocks are so commonplace and available.

Several years ago, I found a deal for $350. It was a 4-bolt 350 motor with a blown head gasket and owner wanted to get rid of it. He had bought the early model pickup from the truck builder and wasn't familiar with the internals. Once I took it apart, I uncovered a forged, balanced crank with Eagle rods and SRP pistons (which were toasted due to detonation), Crower Solid lifter cam, dual roller timing chain, etc.

So, there are nuggets waiting to be found.
 
#24 ·
thanks Kyle
it seems Blueprint has there own cylinder blocks for sale now, 4" and 4.125" bore SBC..

the CCC electric Qjet is the only one that will work with the stock computer setup,
it has the Mixture Control Solenoid and Throttle Position Sensor..
you have to have the correct distributor, and all the sensors MCS,TPS,MAP,O2,ESC,EGR,....
or the whole thing goes into limp mode, the chip/prom can be changed for adjustments
but not for deleting the right carb..
if the mechanic doesn't know this?? he might not be the right one?? does he have the tools/knowledge??

the carb does not really care how big the motor is,
a normal carb just adds a metered amount of fuel to the air flow it see's,
the CCCcarb/computer adjusts that mixture all the time, based on feed back from the carb/sensors
but it may run out of room to adjust the mixture with out carb and computer tuning..
it takes some special tools/knowledge to adjust the carb, and tune the computer, burn or buy chips..

the new 1600$ GM 350 crate motor is just that, its the cheapest new motor youll find anywhere..
its not the best motor for anything, except the wallet and warranty..
the 2000$ L-31/R is a much better stockish hp motor for the money..
but it takes some changes to make it work..

do some searches/readin, ask some more questions..
:texas:
 
#25 ·
JJLT1, I've also noticed that cross members which fit 200R4 are a bit more expensive than those for 700R4's.
I think there all about the same price in those links, the expensive ones at Jegs are kits with mounts,
and I think? the ?84?? and older Elkys need the frame extension for the rearward trans mount location
like the 2004r and th400..

:texas:
 
#27 ·
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top