ok guys- have a question- lets say i want to replace my stock exhaust (ive got an all original l-48) and i want to go true dual, no cats- can a 2.5" system hook up to my stock headers without mods? specifically, im referring to the manifold to exhaust hookup. its getting time to replace the rear muffler/y pipe, and i figure just dump the cat and go dual. as it is now, ive got a hole in my muffler the size of my fist.

seems like the catalogs mention 2.5" and 2.25" depending on engine type

im assuming that a big block engine has a 2.5" manifold, and a small block is a 2" diameter.

i dunno im totally confused on what i should order

i know you guys out there have a good answer for this- havent failed yet!!
stevep31638901.4472337963

Well, when I first went to true duals, my buddy that owns a muffler shop,cut the y pipe just past the manifolds enough for him to start there with the pipes on each side. He went back from there with a short piece of 2 in. and then into a 2.5 into flowmasters. He knew I would eventually put on headers and would go with all 2.5. I eventually went with a set of DynoMax ceramic coated headers. Save yourself the trouble and just put the headers on now

Dave

i see your point- makes sense to me, but what about those dual exhaust conversion kits that mid america and corvette central sells such as these:

http://www.corvettecentralexhaust.com/c3perfdual.htm 

would any of these bolt up to my factory exhaust manifold?

That's the system I put on my '78 L82...it hooks up with no problems to the factory manifolds. It's made for them. Of course...this true dual system is for "off-road use only"!

one of the first two should work.

there were no big blocks in 79... only the l-82...  a slightly peppier small block.

I would recommend replacing the manifolds with headers though.

Make sure to use small tube if you do.  like 1 5/8 primaries converging to a 2.5 and then 2.5 all the way back.

[QUOTE=cthulhu] one of the first two should work.

there were no big blocks in 79... only the l-82...  a slightly peppier small block.

I would recommend replacing the manifolds with headers though.

Make sure to use small tube if you do.  like 1 5/8 primaries converging to a 2.5 and then 2.5 all the way back.[/QUOTE]

That's exactly what I did.... (click here to see)

(changed large image to a clickable link - Norsky)

Paul

Norsky38901.892337963

[QUOTE=LukesVette][QUOTE=cthulhu] one of the first two should work.

there were no big blocks in 79... only the l-82...  a slightly peppier small block.

[/QUOTE]

so i am assuming that the L-82 2.5 system should bolt up to my stock manifolds on an L-48? (i want to switch over to headers at some point, but lack of $$ prohibits that for now besides, i keep reading that the stock rams-horn manifolds work better than people think)

i want the l-82 system so i can order the magna flows with them from corvette central

[QUOTE=stevep316] [QUOTE=LukesVette][QUOTE=cthulhu] one of the first two should work.

there were no big blocks in 79... only the l-82...  a slightly peppier small block.

[/QUOTE]

so i am assuming that the L-82 2.5 system should bolt up to my stock manifolds on an L-48? (i want to switch over to headers at some point, but lack of $$ prohibits that for now besides, i keep reading that the stock rams-horn manifolds work better than people think)

i want the l-82 system so i can order the magna flows with them from corvette central
[/QUOTE]

it should...  doing headers later is fine..  the ram-horns are good as manifolds go..  but arent as good as headers perfomance wise.

thanks for the info guys- think i gots me the info i needs

I bought the 2-1/2" 1974 L-82 pipes from Ecklers. They have a 2" flange that bolts up to your Ramshorn manifolds for about a foot then expands to 2-1/2".

If you decide to go with full length headers, have your pipes installed at a custom muffler shop that is willing to install bare pipes with no cats. The Hooker full length headers aim straight through your crossmember. It is a matter of a straight pipe from the headers back to the rear axle, then 2 90 degree 2-1/2" elbows (available at AutoZone or Advance) to get over your axle. Pretty simple DIY job if you can't find a shop to install the pipes without cats. It is illegal in Nashville and I'll bet it is even more so in regulated NJ.

Dave