81 exhaust manifold options

Truckedup · Posted: Fri Jun 20, 2008 4:38 pm Post subject: 81 exhaust manifold options

Hi,I just got a 81 El Camino ,good running 305 and a 4speed and clutch set up is going in very soon.
I heard the standard exhaust manifolds on these engines are very restrictive.Are there any other stock type exhaust manifolds that are better? I see the center of the engine is pretty much right over the motor mount cross member so I'm thinking the older Ram's Horn manifolds won't clear.
Short steel tube headers would be ok if any of them will clear the clutch linkage.I know some are advertised to clear,but sometimes they don't.Making up an exhaust system is no problem for me.I'm thinking of a single 3 inch pipe back from whatever style of two into one cross over pipe I fabricate,thanks.

CoyoteOn2 · Posted: Fri Jun 20, 2008 5:21 pm Post subject:

First of all ~~~~~ Welcome to the best El Camino Site there is!! You will find alot of great folks here with alot of knowledge willing to share about the El Camino.
Second ~~ Your Question ~~~The Exhaust Manifold is not the prob. regarding restriction, IT"S THE HEADS. A 305's heads have small valves, and small exhaust ports. That's where your restriction comes from. Differant Heads would be more of an advantage than changing manifolds. But then comes the bore size of the pistons, also small, but heads would be an improvement.

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Truckedup · Posted: Fri Jun 20, 2008 8:39 pm Post subject:

Thanks for the welcome! Yes,305's have some limitations that's for sure.The previous owner did a decent rebuild on the engine 6000 miles ago so I'm thinking to keep the engine and adding a small cam.It already has an aftermaket aluminum intake with a 500 cfm Carter AFB and true dual exhaust but small diameter pipes.I was reading around and saw an article in a performance magazine where they modified a 305.A cam ,headers,better exhust and intake -carb,they got about 230 HP.That's probably enough power for me considering the fuel costs today.
I don't think Vortec heads will fit properly,cylinder bore is too small?.So that leaves old camel hump heads froma 283? Probably a head swap would give a bump in compression anyways.

305 modifications

toms84ss · Posted: Sat Jun 21, 2008 9:44 am Post subject:

350 vortec heads will work on a 305 as long as you leave the stock size valves in them. The combustion chamber is 64cc so you will loose a bit of compression if you have 58cc heads. As for manifolds, the L98 350 TPI Camaro and Firebirds had a better flowing manifold then the other F-body cars. These might be a bit easier to find then the rams horn and would offer better clearance. Not sure what headers will clear your clutch linkage. Seems shorty headers would offer a better chance then long tubes. Check with the manufacturer to see what fits.

Truckedup · Posted: Sat Jun 21, 2008 5:00 pm Post subject:

Thanks for the tip on the exhaust manifolds......

lil maddog · Posted: Sat Jun 21, 2008 9:50 pm Post subject:

Truckedup: i have the same exact clutch linkage set-up as you do. Just pulled the motor and trans and put in a 350 small block along with a t-56 viper trans today (almost done). I tried to put a couple sets of long tube headers in the car today and they just didn't want to go from the top of bottom (only on jack stand i don't have a lift). I am going to try and find a set or shorty's tomorrow to try out and put in just to start the engine so ill let you know how it works out.

lil maddog
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1979 el camino 355ci sbc, t56 viper trans, grand national 8.5 rear

Truckedup · Posted: Mon Jun 23, 2008 3:56 pm Post subject:

Maddog,let me know if the short headers fit..........Meanwhile I found a set of LT1 cast iron stock manifolds for short money.These are probably the best flowing stock manifolds.They came of a Camaro and the left and right exits look the same as a G Body.LT1's have a D shaped port but those who supposedly know say they will work fine on the first gneration smallblocks.

lil maddog · Posted: Mon Jun 23, 2008 4:09 pm Post subject:

Truckedup: we couldn't get a hold of a set of shorty headers on a sunday. So we havn't gotten to try it yet (will let you know when i do), but let me know if the LT1 manifolds fit.

lil maddog
_________________
1979 el camino 355ci sbc, t56 viper trans, grand national 8.5 rear

Truckedup · Posted: Thu Jun 26, 2008 3:16 pm Post subject:

Ok,the LT1 exhaust manifolds will not fit a first generation small block head unless the head has the extra bolt holes at each end.The heads on my engine don't have the extra holes....The ports line up pretty good though,just a little clean up work with a grinder to match them up.