I did a '72 Gremlin with a Clifford aluminum intake and 600 Holley 4 barrel mechanical secondary carb. It had the Clifford dual headers and thrush mufflers. Was loud, but boy did it go!

Oddly enough, this Gremlin came from the dealer with a V-8 bell housing and used a V-8 starter. I don't know why. This came in handy because the extra power the engine developed ruined the 3 speed manual transmission. I replaced it with a 4 speed from a Javelin. I don't know if AMC six's from this era can be fitted with a V-8 bell housing and utilize the V-8 starter or if this one was an odditiy.

The fun was that I could walk off and leave a V-8 automatic, let off the throttle, let them catch me, and then go by them again when I floored it! I had to open the hood a lot to prove it was a six because it sounded great. I never opened the engine to change heads or cam unfortunately.

I now have a '77 Gremlin six with the twin headers and Clifford 4 barrel intake. I am using a vacuum secondary Holley 600 because of the automatic transmission and I did a distributor switch to a GM HEI. It runs a lot better than I expected. I mean really strong. But this engine is only temporary.

I am building a 258 for a replacement that will have a mild cam, better performance but should still drive through the Jack in the Box line OK. It will utilize the performance head, but I am buying mine already fixed for use on the older engines so installation shouldn't be a problem. I want to use forged pistons, but still need help in finding such an item. I hope someone will respond who knows a supplier or a suitable interchange for these engines.

I am excited about this. Driving a Gremlin is enough of an oddity these days that I can't wait to finish my 258. I am setting a goal of turbo charging this engine or using Nitrous Oxide. Hence the reason I need forged pistons.

Until then the engine I am using gets really good mileage. If I don't change the cam or differential drive ratio it will continue to get great mileage.

Here are pictures of my engine with details on how I rigged the linkage to the automatic transmission. By the way, hood clearance is not a problem. I used a large Mr. Gasket air cleaner. Look at how much stud I left sticking out of the carburetor for a higher profile air filter. Check it out:
http://www.upmpg.com/projects/amc_gr...etrain_025.htm

Here is a good article on switching to the easier to find parts for and more reliable/responsive GM HEI:
http://www.4x4wire.com/jeep/tech/electrical/hei02/

I would like to keep in touch with and follow the progress of others doing the AMC six performance upgrades. If anyone knows about adding forged pistons to these engines please contact me.