304 Upgrades
JeffP
Senior Jeeper
- Posts
- 536
- Thanks
- 1
- Location
- Peoria, AZ
- Vehicle(s)
- '75 CJ5, 304, T18, D20, D44s w/3.73 1974 CJ5, 304, 4 spd., Dana axles 3.73 gears. 1973 CJ5, 258 I6, T18, Dana 20, Dana axles 4.27 gears. 1972 CJ5, 304, 4 Spd, Dana 20, 4.27 gears. 1976 CJ5, 304, T150. 1976 CJ5, 304, T150, J20 w/4.10 gears. 69 CJ5 Hurricane 4 cyl, 4spd all original! ‘53/‘54 M38a1 100% original but also 100% apart! Low 3 digit Vin! One of the very first m38a1s!
Recently aquired my 5th CJ5. A true garage find, a 1976 with only 50k original miles. This one is the newest of the bunch with a 304, 3 speed manual & power steering.
A few mods had been done like a 4v intake, massive carburetor, GM style HEI, rock sliders, one piece rear axles & headers w/ glass-packs. The workmanship was far from impressive.
First order of business was to replace the 650 cfm carb to a more reasonable 500 cfm Weber / Edelbrock 4v. Next was to plug the multiple exhaust leaks.
While that alone was a vast improvement, it still didn’t run like I thought it should. Missing slightly at idle and occasional “popping” out the exhaust on deceleration.
Having great success with the MSD 6AL ignition boxes previously I decided to try the MSD Streetfire box connected to the GM style distributor. Now it runs like it should! Since the carb change & tune-up it has always started instantly so no improvement there but now not only does it idle perfectly, it performs flawlessly over the entire rpm range!
My only gripe now is that it’s still too loud. I am considering “collector muffler inserts”. Any experience with those or input would be greatly appreciated. I need to reduce the sound by 40-50%.
I installed new factory looking bumpers but 1/4” wall 4x2 tube, a Tigershark 9,000lb winch, new wheels with BFG All Terrain TAs.
It still has the factory soft top, in really nice shape but no bows.
Anyway bottom line... if you havesimilar issues, try the MSD Streetfire box! Personally I think it’s the biggest improvement you can make while spending the least amount of your hard earned cash.
A few mods had been done like a 4v intake, massive carburetor, GM style HEI, rock sliders, one piece rear axles & headers w/ glass-packs. The workmanship was far from impressive.
First order of business was to replace the 650 cfm carb to a more reasonable 500 cfm Weber / Edelbrock 4v. Next was to plug the multiple exhaust leaks.
While that alone was a vast improvement, it still didn’t run like I thought it should. Missing slightly at idle and occasional “popping” out the exhaust on deceleration.
Having great success with the MSD 6AL ignition boxes previously I decided to try the MSD Streetfire box connected to the GM style distributor. Now it runs like it should! Since the carb change & tune-up it has always started instantly so no improvement there but now not only does it idle perfectly, it performs flawlessly over the entire rpm range!
My only gripe now is that it’s still too loud. I am considering “collector muffler inserts”. Any experience with those or input would be greatly appreciated. I need to reduce the sound by 40-50%.
I installed new factory looking bumpers but 1/4” wall 4x2 tube, a Tigershark 9,000lb winch, new wheels with BFG All Terrain TAs.
It still has the factory soft top, in really nice shape but no bows.
Anyway bottom line... if you havesimilar issues, try the MSD Streetfire box! Personally I think it’s the biggest improvement you can make while spending the least amount of your hard earned cash.