I was wondering why there was such a big difference between the GB and GC engine break horse power.

Anyone?

Others here, who are far more qualified than I, will be able to answer this. But, GB is Euro, right? GC, USA. Smog control is my guess. Also possible detuning?

Yup, Steve guessed right - it's smog controlled.

That was a big reason why back in 1975 & graduated college & with a steady job (74 grad year was still recession & layoffs) - that I opted for a used 3 year old 73 914-2.0 at $4700, over the new 75 & 76 GC powered 914-2.0's on the dealer lots - even though my monthly payment was a bout the same due to a longer term (used 80% LTV for 36 mos. vs. 100% 5 yr/60 mos.) on the more expensive $7-8k new ones.

From 73-76 you'll also see an even bigger HP drop on CA vs. "49 state" vs. ROW 1.7, 1.8 & 2.0 motors & in 75-76 they added the Crap-alytic Converter to CA 914s - further lowering them over 49-state/ROW.

This was all smog control induced detuning.

CA buyers should note that DMV/CARB still require smog checks biannually & all equipment on 76> MY, whereas <75 are exempt from checks (technically they should still have their smog equipment intact.

The way I understand it the GA is the detuned US w/ "no smog", GB is the higher compression euro engine & the GC is the detuned US "smog" engine w/ the least amount of bhp. The difference in bhp between the GA vs. the GB is 5 bhp. No idea what the bhp on the GC engine is but it's less than the GA.

http://www.914world.com/specs/engnumbs.php