Summit has a couple different cat back exhausts made by Hooker, one is like $200 while the other is $300, one says 305 HO, and the other doesn't what is the difference and which one can I use, considering I don't have a 305 and neither a cat. Which leads to my next question. Since it bolts to the cat will I have to weld in a piece of pipe to compensate for the missing length or will everything still bolt up.

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'86 IROC
T-TOPS, TINTED WINDOWS, BRAKE LIGHT BLACKOUTS
GM GOODWRENCH 350
EDELBROCK TES HEADERS
FLOWMASTER, NO CAT
EDELBROCK 600CFM CARB.
KN AIRFILTER
ACCEL HEI DISTRIBUTOR
160* Stat
2:73 GEARS
Rebuilt 700R4, with manual valve body
B&M Megashifter
Soon to be installed
3:73 Richmond Gears and 3" Exhaust
"There is nothing more addicting than speed"

 

Having not catalytic converter on your vehicle you can order any one of the cat-backs made for our cars. I ordered the 305 HO one for my 83Z w\ LG4 just last week since I had nothing on my car but headers (haven't been driving it). You will have to get a section pipe frabricated to connect it to your existing y-pipe though.

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83 Z28, 305(LG4), T-tops, T-5 Transmission, Centerforce Dual-Friction Clutch, Hedman Shorty Headers, Hooker Cat-back, Weiand Stealth, Holley 650 Double Pumper

 

ones for a 5.0 HO and the others for a 5.0

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1988 Sport Coupe 305 TBI
K&N
Flowmaster exhaust


Daily driver:
1988 K1500 5.7 4x4 shortbed flowmaster cat-back gutted cat.
AOL: RyanNH84

 

the engine size most likely determines the size of the connection to the cat, and in your case, the y-pipe.I would go with the HO kit, but you should call summit and inquire what the exact difference is.