305 mods? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

magnethead · 07-31-2006, 04:49 PM

My friend has a "305" 1984 GMC C-15 pickup. He wants to know who makes reasonable priced headers and complete exhaust systems (smog equipped) for a reasonable amount of money (works at walmart so not a big budget). The reason I say a "305" is that it has a 6" tall air filter, and after observing some other things (including a very throaty exhaust note), i'm wondering to myself if it still displaces 305 cubic inches.

Scott68-93-97 · 07-31-2006, 04:56 PM

Any small block headers 265-400 will work you need to buy headers per application of what the motor is in, Look into Flow tech afterburners for a smog legal and cheap, edelbrock and doug thorley headers are better but also tough on the wallet, summit makes 50 state headers for trucks also

bwright · 07-31-2006, 05:07 PM

You'll have to check the casting number on the back (drivers) side of the engine block to know for sure what engine you have. Check www.summitracing.com for CARB legal headers. I'd check with a local muffler shop for the exhaust...

magnethead · 07-31-2006, 05:35 PM

the VIN indicated 305, but i'll try to check the casting numbers (being they are so hard to get at).

I checked summit and Jegs, but didn't find much that fit a minimum wage budget and would pass smog testing in the dallas area. I reccomended to him to start out with just high flow headers and Cat just clamped then 2" mandrel bent tubing to connect them with side exits ahead of each tire, then headers.

MylilBowTie · 07-31-2006, 08:18 PM

Check the front pad under the alternator.

magnethead · 08-01-2006, 07:35 PM

Quote:

Originally Posted by MylilBowTie

Check the front pad under the alternator.

I looked, where exactly is it at? I looked at the front face of the cylinder head and couldn't see anything. I thought i saw the code but grabbed a light and screwdriver and I couldn't tell if there was actually a code there or just oil and grime.

MylilBowTie · 08-01-2006, 08:20 PM

If the block has been milled down it wont be there or barley left. I really doubt that the block has been decked. Its directly behind and under the alternator. If you need disconnect the battery and swing the alternator out of the way. Loosen the bottom alt bolt, remove the top one, take the belt off, the alt will be loose enough to turn it left out of the way. Get some carb cleaner and a rag to wipe the pad off to see if there is anything stamped.

07-31-2006, 04:49 PM	#1
magnethead 7000 #'s of american IRON Join Date: Dec 2004 Location: north tx Posts: 883	305 mods? My friend has a "305" 1984 GMC C-15 pickup. He wants to know who makes reasonable priced headers and complete exhaust systems (smog equipped) for a reasonable amount of money (works at walmart so not a big budget). The reason I say a "305" is that it has a 6" tall air filter, and after observing some other things (including a very throaty exhaust note), i'm wondering to myself if it still displaces 305 cubic inches.

07-31-2006, 04:56 PM	#2
Scott68-93-97 Registered User Join Date: Jul 2006 Location: Fair Oaks, CA Posts: 475	Re: 305 mods? Any small block headers 265-400 will work you need to buy headers per application of what the motor is in, Look into Flow tech afterburners for a smog legal and cheap, edelbrock and doug thorley headers are better but also tough on the wallet, summit makes 50 state headers for trucks also

07-31-2006, 05:07 PM	#3
bwright Registered User Join Date: May 2004 Location: Dickson, TN Posts: 141	Re: 305 mods? You'll have to check the casting number on the back (drivers) side of the engine block to know for sure what engine you have. Check www.summitracing.com for CARB legal headers. I'd check with a local muffler shop for the exhaust... __________________ 1977 Chevrolet C10 - 305/TH350, SWB, Stepside, 3/5 drop...work in progress.

07-31-2006, 05:35 PM	#4
magnethead 7000 #'s of american IRON Join Date: Dec 2004 Location: north tx Posts: 883	Re: 305 mods? the VIN indicated 305, but i'll try to check the casting numbers (being they are so hard to get at). I checked summit and Jegs, but didn't find much that fit a minimum wage budget and would pass smog testing in the dallas area. I reccomended to him to start out with just high flow headers and Cat just clamped then 2" mandrel bent tubing to connect them with side exits ahead of each tire, then headers.

07-31-2006, 08:18 PM	#5
MylilBowTie Right turn Clyde Join Date: Nov 2002 Location: Cincinnati, Ohio Posts: 2,911	Re: 305 mods? Check the front pad under the alternator. __________________ 1974 C25 LWB: 454 4bbl Carb / TH400 / 3.73 1992 Camaro RS 305 TBI

08-01-2006, 08:20 PM	#7
MylilBowTie Right turn Clyde Join Date: Nov 2002 Location: Cincinnati, Ohio Posts: 2,911	Re: 305 mods? If the block has been milled down it wont be there or barley left. I really doubt that the block has been decked. Its directly behind and under the alternator. If you need disconnect the battery and swing the alternator out of the way. Loosen the bottom alt bolt, remove the top one, take the belt off, the alt will be loose enough to turn it left out of the way. Get some carb cleaner and a rag to wipe the pad off to see if there is anything stamped. __________________ 1974 C25 LWB: 454 4bbl Carb / TH400 / 3.73 1992 Camaro RS 305 TBI



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