853's vs 243's
 

What are the differences between the two heads?

Look at this thread titled, "853 vs 241 heads" (I know it sounds familar);

https://ls1tech.com/forums/generation-iii-internal-engine/666164-853-vs-241-heads.html

Start searching!

Moved from Advanced Tech section.

The 853 heads came standard in most '97-00 LS1s. They had 67cc combustion chambers. They were superceded by the 241 castings, but the flow and performance were virtually identical.

The 243 heads were introduced for the first time in the '01 Z06 Corvette. They featured higher flowing ports, smaller combustion chambers, and for the Corvette only, they also had lightweight valves. Today, the 243 head is used in many GM applications from the LS2 engines used in C6, GTO, Trailblazers, to the 4.8 and 5.3L motors in GM trucks and SUVs. They are a nice step up in power compared to the 853 heads.

Thanks for the link..but I wanted to know about the 243 heads.

Thanks Patrick. I just wanted to make sure there weren't any significant differences in the short turn radius or anything along those lines....

Well, nevermind on my above post, but do keep searching.

The 243s are wider at the SSR and the bowl is notable larger. They lend themselves to more flow with those changes. The roof is trajectory shaped (LS1 head is not), the swirl vane is less pronounced, and the exhaust ports are D-shaped.

They're worth good power over a LS1 head. LS1 heads all perform the same with a VERY small difference from 853 to 241 casting.

Ben T.

There are differences there. It's wider, taller, and better.

Ben T.

I'm buying a ported set, so there won't be any concerns I guess.



Thanks all, especially for the creative editing...

...but I'm not convinced if it makes more power.

Anyway, what are you buying?

Stage II ported heads. 303cfm on the intake. 195 on the exhaust.

853 were 1997 - 2000 LS1 heads. 67cc chambers, single quench, sand cast.
243 were 2001+ LS6 heads. 64cc chambers, double quench, semi permanent mold.

Stock LS1 Heads
Chamber 66.67 cc 0.100 0.200 0.300 0.400 0.500 0.550 0.600
Intake 200 cc 67 122 178 215 219 223 227
Exhaust 70 cc 52 97 133 156 170 176 180
Valve Diameter Intake 2.00"
Valve Diameter Exhaust 1.55"
Part Number 12559853 (1997-98)
12559853 (1999-00)
12564241 (2001-03)


Stock LS6 Heads
Chamber 64.45 cc 0.100 0.200 0.300 0.400 0.500 0.550 0.600
Intake 210 cc 62 126 184 224 251 256 257
Exhaust 75 cc 57 108 143 163 176 180 183
Valve Diameter Intake 2.00"
Valve Diameter Exhaust 1.55"
Part Number 12564243 (2001 +Z06)