xrwagon
Well-known member
First up peeps, my car was running ok last weekend, apart from taking time to warm up, bit longer than i thought i just persisted, drove to a car show and swap meet in town, then another car show. Then on Monday i had her booked in for exhaust mods. The extractors were cut back at the merge where the 3 go into 2, there was a large overlap in the pipe there, pipe size i think we went up qtr inch over what it was, then ran twin into a 3” collector, single 2.5” exhaust and a custom spiral auger muffler that was made by my mate at the muffler shop. When i picked the car up it was loud, even louder than my 2.5” collector with no exhaust and this was with the exhaust, being a race muffler this was a trade off because the improvement in performance was substantial. Bu it ran rough, like the whole tune was out. I am running a slightly worked 250 2V head, factory manifold thats been modified and a 350 Holley, the Holley seemed to like being jetted up and ran its best with 70 jets and a 6.5PV, not sure why but it went well. Running so roughly i pulled out the plugs, all fouled, cleaned and regaled them one was closed right up like it had been dropped, gapped at 40. Reset the mixture screws and idle, i decided to go back to a 8.5 PV and dropped some jet so down to a 68’s. Back to the muffler shop and changed this muffler, to loud, and got a regular performance one (Redbak), sounds so much better, rough running is still there and i am scratching my head. Any thoughts?