AMC 360 mild performance rebuild thoughts?

[posulli88]

I have decided to pull my engine and do a rebuild. I was chasing too many things in the engine and finally came to the realization it was best to pull it and do a rebuild and get it over with:

http://forums.ifsja.org/showthread.php?t=183455

If I am going to go through the hassle of pulling it and rebuilding I might as well add some performance. I know this is been posted quite a bit but I would love to get this forums advice and opinions as I have never had an engine rebuilt.

Here is what I have and know:

I plan to use this truck as a driver, (wont be towing anything may haul light loads). Id like to add more low end torque and horsepower but I don't need anything crazy. I would like to do this as cost efficiently as possible. That doesn't mean I want to use cheap parts just don't need to go crazy on this thing. Just looking for some added power while being able to maintain daily driving.

_AMC 360
_T18 transmission with Dana 20 Transfer case
_I just had a valve job on my heads (all new valves, seats, guides, and seals)
_I have a brand new Edelbrock 2131 intake
_Have a used but good condition Edelbrock 1406

Im planning on:

_double roller timing chain
_Oil pump rebuild
_Clevite bearings
_Mahle Gaskets

Questions:
_Was looking at a Edelbrock performer cam (but like the aggressive idles of some of the comp cams) I know to avoid the 8600. What do you guys suggest?
_Is it worth over boring .03 and doing something like wiseco pistons, or for the money should I just stay stock?
_Would I need roller rockers or would stock bridged rockers be ok?

Thanks for your thoughts everyone.

[440sixpack]

How much you bore will depend on what your machinist determines to be required. you might end up a .060 over.

The cam is going to depend on what you want to hear more than how much power you want. without compression to match lumpy cams are just for audio entertainment. the brand doesn't matter look at the grind. using comp as an example a 270H will give you a lumpy idle and no low end torque. sounds cool, runs crappy. start there and work your way down until you find what you want, I wouldn't suggest much more than stock on a pick up cam.


Your biggest and toughest call will be pistons. I found very little to choose from for a 360 when I wanted a mild upgrade. plan on running 91 octane if you go over 9 to 1 compression and a race fuel - 91 mix if you go over 9.5 to 1. the choice is yours just remember power always comes with a price tag in old engines.

I'm glad you decided to do it right and get it over with. in the end you'll be glad you did.

[babywag]

I built pretty much exactly what you're talking about. Took a bone stock 360 and added a Comp Cams 270H cam, lifters, and springs. Also put on an Edelbrock air-gap intake, holley carb, and Edelbrock headers. The ignition is upgraded with an MSD box. Aside from that the engine is all original. I put it on a chassis dyno and made 255.6 hp / 364.1 tq to the wheels. Easy as cake.

No reason not to go a little bigger on cam if you want.
Don't "need" pistons to make power, Don't "need" race gas if you do replace 'em.

As in your other thread opinions vary, but in real world these do make power even with stock cr pistons.

[440sixpack]

No cam will make big power with low compression. might as well turn your air cleaner lid over it will do the same thing .


If you have proven otherwise your fortune awaits you. I wouldn't be giving it away on a dumb forum.

[Nikkormat]

I don't think he's looking to make big power, I'm guessing he's not even looking for a horse power per cubic inch.

There is more to power than just compression and cam. Those are merely items to support MORE power. Flow is what makes power.

If you took Greg's formula quoted into a previous post, and combined that with some headwork, you could have a 300hp (to the wheels) 360 very easily.

OP says he has heads with a fresh valve job, a 2131 intake, and a 1406 (600 cfm) carb. I say...
- Do some light port work to the heads. Just clean up casting errors, smooth transitions, and match the heads and intake to the gasket profile.
- Before you decide what you're going to do with the Pistons you need to figure out what machine work your block will need. There is more to compression than just the CC of the piston relief. You need to consider how far below deck the piston is, and how far your heads have been surfaced (the volume of the combustion chamber).
- Then after you know those dimensions you can plug it into a compression calculator and choose a head gasket thickness and piston volume. For us AMC people the only really good option for thinner head gaskets are Cometic MLS gaskets. Sadly about $80 a piece but that is a small price to pay to have your engine not ping.
- Then you can pick a cam or three, plug there specs into a dynamic compression ratio calculator, and it will spit out your dynamic compression ratio. That's the number you need to worry about for ping. And you can get that number up around 9.5:1 with proper quench and have no problems on premium pump gas.

[440sixpack]

Good advice. but with the limited selection of off the shelf 360 pistons it may not be easy to get there. custom pistons are an option if you want to spend a little more.

Read Comp's comments on the 270H and it will show why you want to look at less cam . if you didn't have your guides cut for positive seals you're going to need to consider that as well.

https://www.summitracing.com/parts/cca-12-211-2/overview/

[Mikel]

One very cheap upgrade for low compression engines is narrowing the ignition timing so that you have more initial timing. I've run 20deg BTDC (35ish total minus vacuum) and it makes a huge difference in low RPM torque and throttle response over the stock timing. The only problem is that hot starts can be more straining on the starter.

[posulli88]

I definitely want to be able to use pump gas but am ok with using 89,91, or 93 (all available here in MA). I currently have an HEI distributor and plan to continue to use that. I will look into a couple specific cams and get peoples thoughts on them. I know thoughts on cams here are varying...

[Mikel]

I definitely want to be able to use pump gas but am ok with using 89,91, or 93 (all available here in MA). I currently have an HEI distributor and plan to continue to use that. I will look into a couple specific cams and get peoples thoughts on them. I know thoughts on cams here are varying...

Most HEIs have 15degrees of centrifugal advance, as opposed to 25ish for stock distributors.

Get a dial-back timing light and set it to 35 deg at 2500-3000 RPM (with vac advance unplugged) and see how it runs. You may have to dial back the vac advance a bit, as a lot of HEI distributors come with way too much vacuum advance and will cause pinging at part throttle.

[440sixpack]

The thoughts vary. the facts do not.

You just need to decide what you want and what it's worth to you to get it. then the manufacturers word for it.

[babywag]

Yeah, cuz those dyno sheets lie like the dickens

[posulli88]

Will stock bridged rockers be ok to use with increased power? Or do I need to use roller rockets?

[Nikkormat]

The rockers with stamped steel bridges should be fine to around .510 lift.

The summit 8600 would probably be a good cam for you, I don't know why everyone hates them so much. The 270h is too much cam for your application.

[Ristow]

yeah,the bridged rockers will be fine. but check them out to be sure they are in good shape. clevite makes good replacements.

[Ristow]

i would get the comp cams high energy timing chain,its a link belt style. i no longer like roller chain timing chains,i have seen how they stretch.

i like torque right off idle,and a broad power band. with your manual transmission tho you can go a little more aggresive on the cam. i would stick with the performer grind myself,but would get an elgin cam in that grind.

i liked victor reinz gaskets. i think i read somewhere they got bought out and are crap now tho...?

you can get decent power with the stock pistons. the wiseco would be nice as well. purely up to you. if i were in your shoes i would probably forgo the wiseco pistons,and stick the money in better rockers.