1990 LA 360 roller motor

I just bought a 90 360 roller motor with 74,000 miles on it. It is the throttle body FI engine. It came out of a 90 D250 pickup. I am putting it into a 73 Cuda. I plan on initially running it very mild; Edelbrock Performer intake (already have it on my 318), Holly spreadbore carb (also on the 318) but could go with a square bore Holly carb (any advice?), headers and stock OEM electronic ignition. Obviously the FI will go. It has the 308 heads on it. I am having difficulty finding the compression ratio of this engine. I understand stock it has 193 HP and 292 TQ. I think with the swirl port 308 heads it is around 9.0-1 ratio but I can't get confirmation on that. Anyone know the compression ratio? Also would like to hear comments on my future build idea keeping the bottom end stock:
1. port, polish and put bigger valve in the 308 heads
2. keep the Edelbrock intake but port match
3. keep the OEM electronic ignition but add an MSD box
4. put a bigger cam in it, something like the 268
5. headers
I would like to think with this combination I can get at or near 400 HP and 400 + TQ. This car will be a cruiser/driver that can give some spirited performance. One last question: I ran across on Allpar this statement by someone about using a carb on a fuel injection engine:
"I decided that TPI (Throttle Point/Body Injection) “stunk”, and I wanted to go to a simple 4 barrel carburetor and call it a day. But the swirl port heads and lower compression ratio of the heart shaped combustion chambers inside of the 1988 and older fuel injection heads (which were present on my 1990 boneyard motor) would not be “carb-friendly,” so I opted for 1983 police heads."
Any idea if this is accurate, can I expect issues with what I want to do and what can I do to eliminate any issues that there may be. This individual either has experienced an issue doing this or knows of someone else who has. If not, not sure why he had posted this.
Thanks in advance for any input, comment and advice.

I would run the motor as-is. I have an 89 TBI 5.9 myself and will be doing just that. It's a jasper rebuild with something like 1500 miles on it so that's why I scooped it up, but then again I am not looking for performance.
If you want 400 HP then I suggest you get a magnum motor and follow the low buck build that Mopar Action did last year or year before.

The 400hp magnum headed build is simple and laready figured out for you.

working the 308 castings over for more flow then choking them with a Performer intake seems foolish to me.

As for the Allpar comment, he's wrong. There is NOTHING heart shaped about the 308 head's combustion chamber, nor is it's compression ratio any lower than any smog era engine. He's probably thinking of the 302 castings on the 2bbl 318's which A. came with a carb from the factory and B. works just fine with a 4bbl carb as well, BTDT.

The compression ratio on the roller 360 was rated at 9.2:1. HP was rated at 170 with 260 torque, about the same as an early 70s 318, although supposedly you can get more out of the 308s with a good set of headers. They are not bad motors, they just need more work to get them moving.

Some good info here:
http://www.forabodiesonly.com/mopar/threads/roller-cam-swap-in-1991-360.113418/

Minimal information there of use, most of it is fantastically wrong.

Here's a gem "have the smog ports welded up, gasket match them"

Yeah, that's a good piece of advice

I was talking about the valve springs and cam specs, I did not certify the entire thread as being to your standards. Feel free to post any relevant info helpful to the OP that you can find on the web.

1) There is nothing special regarding those 308 casting heads - basically junk. Don't put any kind of money into iron heads aside from basic clean up anymore.

2) Port matching on something that mild will yield no noticeable results.

3) Standard Orange Box is fine. An MSD might make a noticeable difference in idle quality if your tune is off.

4) Why buy a roller motor then stuff a flat tappet into it? I would look into getting the factory roller cam reground. Could probably even reuse the lifters.

5) Headers are a must if you want to see 400HP out of that.

If the bottom end looks good, then put a set of heads, a cam, a better intake, center sump oil pan and a set of headers on it.

Enginequest heads or aluminum heads would be my vote. Find an RPM Performer intake used somewhere along with the oil pan and pickup tube.

Both Summit/Jegs have a cheap center sump pan for $50. Pair with a melling pick up.

https://www.summitracing.com/parts/sum-g3536

Might be worth reading this thread, magnum headed LA roller. Watch with the exhaust manifolds, though.

http://www.forbbodiesonly.com/moparforum...ine-swap.96118/

There was a lot of horsecrap in the few replies, with gems in some of the followups.
Here's what I know:

Any number of 360s have hit the 400hp mark with stock heads.

The 308 heads have about the same intake ports as a 360 smog head. Their exhaust ports are much better. They work best with a single pattern cam. Too much exhaust duration lets potential horsepower out. Their combustion chamber is your basic Mopar open chamber, meaning no shape except for nearly round.

There is absolutely no need to use larger than stock valves on this head. What would help the most is work on the intake ports. There are a few articles floating around, the best IMHO being the one written by Steve Dulcich on porting smog heads. BTW, before you pay someone to port your heads, get a written quote. Those aftermarket heads may look better after you find out the head shop's total cost. Plus, most head shops don't like to work cast iron, it's dirty and takes longer.

Note that I didn't use the word "polish" anywhere above. That term went out of fashion when it was discovered that rough intake port walls make more power than shiny ones. Polish the combustion chambers and exhaust ports if you wish but it's a lot of work for very little gain.

Port matching and/or opening the ports to gasket size won't do a thing. If you have OCD, you should probably do it or else you'll be doing it later. Otherwise, just say "no".

Your factory roller cam is the best way to go. Regrind it. Call up Bullet and Delta and ask them how close they can get to a Comp XE268. Bullet may still be $120 for the regrind, Delta may still be $100. Not expensive at all.

Valvesprings should be replaced, I suggest Hughes 1110s. Also check the clearance between valve retainer and valve oil seal. There's not a lot of room in there. That's also why I picked the Hughes springs, they have about the least compressed height.

Let's talk about aftermarket heads. They will come out of the box flowing as much as a ported 360 head. But the prices! More than for a bigblock head. There's Enginequest's cast iron head, Edelbrock Performer heads, the ProMaxxhead, the Sidewinder and the Speedmaster (ProComp Electronics).Of those four, the edelbrock is the only Made in USA head. The Speedmaster heads are the least expensive and have much have quality castings, according to some posts I've seen. The benchmark for this group of heads is the Edelbrock Performer. The value leader is the Sidewinder head. It should take hundreds off the Edelbrock price. The Sidewinders are built to your specifications and should be ready to go out of the box.

R.

I did.

400hp with untouched magnum heads is stupid simple and easy.

No need for porting, no need for overly lumpy cams, no need for anything trick, special or made of unobtainable. Or particularly expensive.

It is, essentially a intake and cam swap on an otherwise stock magnum 360.

Thanks for the responses here. I thought about aftermarket heads but heard how some think the 308's are some of the best non-magnum heads MOPAR ever produced and can perform as good as some of the expensive out of the box heads. I will re-think that and since it looks like I can get a set of aluminum heads for about $1300 that looks like the better way to go. I am assuming that conversion to magnum heads with the additional cost of rockers and push rods will come within $300 of the aftermarket ones mentioned here and they would still be iron. I'm liking the aluminum options better the more I think about it. Also thanks for the clarity and comment on the info I quoted from the Allpar article I read. I doubted its accuracy but am by not means an expert and highly regard and have faith in what I find here on Moparts. didn't make sense to me and he never stated the whys so that took away credibility from the article for me.

Thanks again.

I know from testing that a performer 318/360 with port matching will run right close with a rpm or air gap. If it's worth it to you to spend the money on a new intake, go for it. If not, open up the intake you have a bit and blend it back into the ports.

308's love to crack, so be aware before spending a penny on them.