300 hp combo for 360 la

[Mopar69]

So I'm buying a 1990s 360 la the tbi has been carb swapped and before I put it in my truck ( 83 w150 np435) I want to go through it and add some hp while it's pulled, this is going to be somewhat of a daily but I still want to be able to light the tires if I need to, I'm looking to make 300 hp without boring it over, if possible, any suggestions welcome

 

[HemiLonestar]

Boring it over doesn't necessarily make more power, except when in conjunction with a stroke increase to increase overall displacement. There is no automatic correlation to cylinder boring and more power. People have always thought so; dunno why.
Hopefully the carb swap came with a decent intake manifold. I believe your year should have the 308 heads. Are you sure the 360 is an LA? The 360 LA only made it a few years into the 90's, after that it was all magnum. 308's aren't the best LA production heads but should be able to do what you want.
A 90's LA will already have a roller cam ( a small one .391/.391 - 240/240); this makes for an easy cam swap (no break-in required) though I'm not sure if the selection is as large as the available flat tappet cams.
A little compression increase would be good too but if you just want a little more power than still burns regular then I'd leave it at the stock CR (about 9:1 if memory serves).
The right cam with a good intake manifold & exhaust (and tuned correctly) should give you what you want. If you haven't upgraded already a performance distributor would be a worthwhile investment (plus the orange ignition box).
If it's in the budget, better heads would also be a good idea.

 

[Mopar69]

It does have a good intake on it, it's a Edelbrock high rise i think, not too sure but what would you recommend for a cam and heads, I do remember it has the la manifolds on it so I'm confident it's the la still

 

[HemiLonestar]

Hughes is probably your best bet for LA stuff anymore. Edelbrock apparently doesnt' do the lower power street packages anymore; this kit is overkill for your stated goal: https://www.edelbrock.com/performer-rpm-top-end-kit-for-s-b-chrysler-2049.html
It's also a flat tappet cam. They make decent heads, I believe Hughes has some as well. Later magnum heads can be adapted but by using AMC lifters to oil up through the pushrods but that is for flat tappets, so far as I know that doesn't work for the roller cams.
Browse away: https://www.hughesengines.com/Index/products.php?browse=category&level0=QS0gU21hbGwgQmxvY2sgIkxBIg==
I would contact them, give them your goal and see what they say.
I've noticed over the years that some of the LA & B/RB parts I used to take for granted don't exist anymore.

 

[Mopar69]

Hughes is probably your best bet for LA stuff anymore. Edelbrock apparently doesnt' do the lower power street packages anymore; this kit is overkill for your stated goal: https://www.edelbrock.com/performer-rpm-top-end-kit-for-s-b-chrysler-2049.html
It's also a flat tappet cam. They make decent heads, I believe Hughes has some as well. Later magnum heads can be adapted but by using AMC lifters to oil up through the pushrods but that is for flat tappets, so far as I know that doesn't work for the roller cams.
Browse away: https://www.hughesengines.com/Index/products.php?browse=category&level0=QS0gU21hbGwgQmxvY2sgIkxBIg==
I would contact them, give them your goal and see what they say.
I've noticed over the years that some of the LA & B/RB parts I used to take for granted don't exist anymore.

I'll check them out, thanks

 

[diymirage]

It takes more effort to get less than 300 HP out of a 360, than more

 

[David Vandercook]

Try adding a hood ornament and flipping your air cleaner lid upside down.

 

[u2slow]

My '90 360 is an LA. Magnum didn't arrive till 92?

I would be looking at pistons (more compression) and a new cam profile. If the heads are cracked, and/or depending on machining cost, might consider aluminum heads.

 

[diymirage]

My '90 360 is an LA. Magnum didn't arrive till 92?

I would be looking at pistons (more compression) and a new cam profile. If the heads are cracked, and/or depending on machining cost, might consider aluminum heads.

usually, LA heads do not crack near as often as the magnum heads do

I have an LA in my duster, 408 stroker with iron heads
even with those worked over stock heads she dyno'd at 420 ish HP

 

[u2slow]

usually, LA heads do not crack near as often as the magnum heads do

I hope that holds true for me. Mine has over 300k on the ticker and had a dual-fuel propane conversion.
I've only read about the cracking, which sounds more common with the TBI heads than the older ones.

 

[diymirage]

300k is nothing to sneeze at

does a propane conversion require hardened valve seats ?

the TBI heads are definitely a magnum thing, so that may be it

 

[u2slow]

A purpose-built propane engine gets hardened seats. No telling what mine has, but I suspect it's still factory original.

TBI heads came on the late LA engines. Magnum is different - pedestal rockers, different oiling, etc.

 

[HemiLonestar]

My '90 360 is an LA. Magnum didn't arrive till 92?

'93. The 5.2 was the year before.

the TBI heads are definitely a magnum thing, so that may be it

No, TBI is still LA, but it's LA with a roller cam. Magnum heads are more like SBC heads (no Mopar rocker shaft).

 

[diymirage]

'93. The 5.2 was the year before.


No, TBI is still LA, but it's LA with a roller cam. Magnum heads are more like SBC heads (no Mopar rocker shaft).

View attachment 567972

Oh yeah, I always forget about those

I'd love to have one some day...all the coolness of an LA, none of the headache of a flat tappet

 

[Wild one]

'93. The 5.2 was the year before.


No, TBI is still LA, but it's LA with a roller cam. Magnum heads are more like SBC heads (no Mopar rocker shaft).

View attachment 567972

I think the AMC engineers were the ones behind the Magnum heads.When Mopar bought out AMC supposedly their engineers went with the package.I think the Magnum heads were very close copies of AMC's dogleg heads