uhcoog1

I'm looking for some feedback on running shorty headers with no cats with a decent sized cam. Anything in the 227/235 @ 113 on up to a 242/242 @ 106. Specifically I'm curious if the overlap is a problem without long tube headers. I'd love to see some dyno graphs from anyone who has run shorty headers with ported heads, decent sized cams, etc. Especially those who do it with a 5.7.

My motor is limited to shorties due to packaging restrictions in the engine bay (new gen swap in old iron). Shorty headers into 3" x pipe, mufflers, and dumps.

99Bluz28

iTrader: (35)

Even with shorty headers if you can get 1-3/4" or better yet 1-7/8" primary tubes, and with 3" collector exits all the better! As far as cams, I don't see a single pattern cam working best for you, a traditional split cam would give the best results with a restrictive exhaust.
So what car is the LS1 going in?

uhcoog1

Well, it's actually a gen III hemi going in a 73 plymouth duster. I usually look to LSx guys for advice, as the motors are quite similar, and ya'll are 10+ years ahead in knowing what works and what doesn't! And only a handful of hemi guys run anything larger than the 218/224 I currently have...

The primaries are 1 3/4". Building the car to road race - cam in the motor right now measured at a 218/224, 113.5 LSA +3. XFI exhaust lobe profiles for both intake and exhaust. The plan is to dyno the motor, then decide what changes (if any) need to be made.

99Bluz28

iTrader: (35)

Auto or manual transmission?
What size rear gears?

uhcoog1

manual - tko600
3.60 ring gear

99Bluz28

iTrader: (35)

I actually think you'd be good with a 227/235 113lsa(or very similar cam) , you've got a 8* split and +5* overlap which isn't very much, but I couldn't say for sure if you want to go with anything larger or with narrower lsa.