Want to beef up Pacer inline 6

[cfd]

I've got a great low mileage 75 Pacer that I love to drive. Only problem is that it can't get out of the way with its 1bbl carb, smog controls, etc. I see that there are some Jeep buildups for this same basic engine. I'd like to hear any suggestions or experience you guys have related to building up a 6cyl. My goal would be to get a car that can do 0-60 in under 8 seconds. What's out there, as I want to get this thing under way.

Also, if anyone knows of a pair of Pacer Sport Seats in any condition please let me know... Chris

[Big Bad AMX]

Does your Pacer have a 232 or 258?

[Kem]

I've got a great low mileage 75 Pacer that I love to drive. Only problem is that it can't get out of the way with its 1bbl carb, smog controls, etc. I see that there are some Jeep buildups for this same basic engine. I'd like to hear any suggestions or experience you guys have related to building up a 6cyl. My goal would be to get a car that can do 0-60 in under 8 seconds. What's out there, as I want to get this thing under way.

Also, if anyone knows of a pair of Pacer Sport Seats in any condition please let me know... Chris

Hi Chris, Not sure of how far you want to go with your Pacer build up, but here is what I did to my Concord 258 to wake it up.
The first thing replaced was the cam, I went with a CompCams Extreme series cam. Comp says the cam is good for better mileage and more low end torque. This cam has about 250 degrees of advertised duration with lifts of about .480. Its a high lift short duration cam. It has a good idle, not lopey. Check the CompCams website.
I added the head from a 4.0 Cherokee. If you want to replace the head with the 4.0 head be SURE to use the #7120 head, used on the 91 and up 4.0. DO NOT use the earlier head, 87-90, as it has reliefs in the intake ports that make it tricky to mount the intake. The reliefs are for the injectors the 4.0 uses, and the 4.0 uses an intake desiged for this, but you will most likely be using a carb and intake. The 4.0 head has a much better designed intake port which is better then the 258 head port, which makes a 90 degree turn from the intake to the chamber, but the 4.0 makes about a 45 degree turn. This is good for power and mileage. If you use the 4.0 head you must use the 4.0 exhaust tube header, and an intake from an 81 up 232 or 258. There are a alot of 2 bbl intakes available from the 81 up cars. When using the aluminum intake and tube header you will save about 50 lbs of weight over the cast iron original intake and exhaust manifold.........There is a website devoted to the installation of the 4.0 head on the 232-258. After doing my changeover, it was clear to me that the website left alot of information out, or they had not really done a changeover as they state. Be leery of some of the internet info about this. I had alot of headache because of that half-assed info they gave.
I increased the size of the exhaust from the small pipe to 2-1/2 inch pipe all the way to the bumper. I think the original Concord muffler had a 1-7/8 exhaust side to it!!! This increase to 2-1/2 from the 1-7/8 helps exhaust flow alot.
For a carb I used the Holley 2100 2bbl on my aluminum AMC intake. The Holley will not fit the mounting on the intake, as it was built for the dreaded Carter BBD 2bbl, but I used the Mr. Gasket carb adapter #1937 to fit it on. You can also use the Motorcraft 2bbl from a 304 or 360 AMC, or even from a Ford 302, 351, or 400. The good thing about the Holley is there are so many parts available for it to set it up the way you want. I have the Holley jetted very lean and get about 21 miles a gallon now, but got 24.5 mpg when I had the Motorcraft 2bbl from a Gremlin on it. I may go back to the Motorcraft, but the Holley looks really good sticking out from under the air filter, looks like the front of a 3310{Holley 750} under there!
I added the MSD 5 box, and MSD B'laster coil. I upgraded the cap to the big Ford cap, the one used on the 80's Ford 300 inch six cyl's. It will fit the Motorcraft distributor if you get the cap adapter from a boneyard, or it is also available from AutoZone. Be sure to spec the brass contact distributor cap, and not the aluminum contact cap.
Right now I am using the SplitFire plugs. Using the MSD coil, I can gap the plugs to .055. I was using the Bosch Platinums, and believe it or not the SplitFires have a little more kick to them. I am running about 10 degrees of advance, and I do get some rattle when using 87 Octane, so I add some Shell 93 octane, about 5-6 gallons to the tank to clear up the rattle problem. The 258 is running with stock compression ratio. The block was bored .030 over and the head was decked .020 , so maybe this is adding to the rattle problem.
I have never timed the Concord to see what the 0-60 time is, but I would have to say it can do it in under 8 seconds. The Concord has a very steep rear drive ratio, about 2:60, so considering that, under 8 seconds is not too bad. Your Pacer probably has about the same rear end in it. I think the Pacer is a heavier car then the Concord. Doing the above mentioned upgrades to the Pacer should help it alot. Good luck with the Pacer....Kem

[Gremil]

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. :D

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_gremlin/engine_drivetrain_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. ;)