Looking for some input on 360 LA build

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Josshh70

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Hello guys, I'm finally back after a few months since getting my junk mabbco engine. However the $2,000 paperweight is finally going to make some progress. I have recently tore down the engine completely and had a local machine shop check the block to make sure it was all good. Only cost me a couple hundred. However moving onto the build of it I'm looking for some input on some components, so here's what I got so far.

block- 1991/1992 LA roller block

crank- Stock 360 la crank

Carb- Edelbrock avs2 650 cfm 4bbl (edl-1905)

Intake- Weiand action plus (8007wnd)

Camshaft- Howards cams 711915-12

Pistons-Keith black 107 4.040 (UEM-KB107-040)

Lifters- Elgin HL-2269s with stock dog bones and spider

Pushrods- stock pushrods

Rocker arms/rocker shaft- stock rocker arms and shaft

Timing set- comp cams 2103

Headers- hedman 79080 long tubes

This is everything i have so far for this engine now here comes my questions

What heads should I use? I see trickflow, speed pro , and edelbrock all have some nice looking heads looking to stay under the $1,600 range on some nice aluminum heads.

Also will I encounter any piston to valve issues, I have yet to measure deck height with the rods and pistons in the block but based off the cam size and rocker ratio and stock pushrods I was wondering if it would even be an issue.

I'm also torn on my connecting rods if I should get a set of scat I-beam rods or a set of speedmaster H-beam connecting rods, either way I am going to have to get the crank re-balanced as I changed my piston and rod setup.

And finally the long drawn out controversy on the oil pumps, should i go with mellings high volume or standard volume i don't know if it makes a difference just looking for someone's 2 cents.
 
Did you buy/get all this as a long block?

your pistons needed to be ordered after or same time you make decision on compression ratio and heads.

make plan... then buy parts.
 
autoxcuda said:
Did you buy/get all this as a long block?

your pistons needed to be ordered after or same time you make decision on compression ratio and heads.
make plan... then buy parts.
Click to expand...

The only components I'm re-using from the long block I received from them is going to be the pistons, rocker shafts and rocker arms, the block and crank too. The rest of the components I have listed I already have from a previous endeavor on a 318 build that ended up never happening.
 
Use a Melling m72, skip the high volume.
On the later blocks you need to look out for flashing in the lifter bore feeds.
Buy some promax heads. Don't waste money on speeddisaster or edlebroke.
If you need more, trick flows.
 
Josshh70 said:
The only components I'm re-using from the long block I received from them is going to be the pistons, rocker shafts and rocker arms, the block and crank too. The rest of the components I have listed I already have from a previous endeavor on a 318 build that ended up never happening.
Click to expand...

I’m thinking with that cam, you’ll be looking for 9.0:1 to 9.4:1 compression

now use Wallace calculator with piston specs to figure out what head CC’s give you that compression....

3.58 stroke
4.04 bore
6.125 rods
1.675 in. Compression distance
5 cc piston dish
 
Last edited:
autoxcuda said:
I’m thinking with that cam, you’ll be looking for 9.0:1 to 9.4:1 compression

now use Wallace calculator with piston specs to figure out what head CC’s give you that compression.
Click to expand...
If he can build.. by the time he relieves the chambers and knocks the edges off.. they will be a hair bigger and close to his goal
 
MOPAROFFICIAL said:
If he can build.. by the time he relieves the chambers and knocks the edges off.. they will be a hair bigger and close to his goal
Click to expand...

with what advertised head cc?

I plugged these numbers to get under 9.5:1 compression. Please point out any mistakes.

493DEF60-0635-43BA-AD0E-B500F36E6768.jpeg


2B31F17B-87C9-4782-BE68-007691BFF12A.jpeg
 
Posting the actual cam specs is SUPER HELPFUL!
Posting part numbers is OK at best. Saying or describing what it actually is, is better. Example; your comp timing chain. You have one! Terrific! There are so many options to which one it is and I myself (and few others) will not look it up to know exactly what it is. No one wants to do the homework on answers you should have provided.

As far as what head to use, it would be the best one you can afford. Hands down! Maxx 171 SB Mopar (Sold in Pairs) - PROMAXX Performance Products
Though I say to make the stretch and get ether;
Shocker 185 Mopar CNC (Sold in Pairs) - PROMAXX Performance Products
Or the Trick Flow heads.
 
autoxcuda said:
with what advertised head cc?

I plugged these numbers to get under 9.5:1 compression. Please point out any mistakes.

View attachment 1715748380

View attachment 1715748381
Click to expand...

At 65cc, 68-70 isn't far away.
Ex. 62cc ends up about 65-66cc after chamber work. I'm not sure what so bad about being a hair higher. What's the cranking gonna end up like.
I'm not going to do fuzzy math atm.
I'm not on the clock. Lol
 
MOPAROFFICIAL said:
At 65cc, 68-70 isn't far away.
Ex. 62cc ends up about 65-66cc after chamber work. I'm not sure what so bad about being a hair higher. What's the cranking gonna end up like.
I'm not going to do fuzzy math atm.
I'm not on the clock. Lol
Click to expand...

I’m not feeling the OP has Head CC’ing tools. Maybe I’m wrong?

Well here are the cam specs....

I think you need a cam card with more specs than this to figure out cranking compression. But I don’t get a vibe this is going to bleed cyl psi. Others thoughts???

Year:
 1964 - 2003
Make:
 Chrysler

Engine:
 273, 340, 360

Camshaft Type:
 Hydraulic Roller
Basic RPM Range:
 1200 to 5700
Valve Lift Intake:
 .475
Valve Lift Exhaust:
 .500
Duration Intake:
 274
Duration Exhaust:
 278
Duration at 050 Intake:
 221
Duration at 050 Exhaust:
 225
Lobe Separation:
 112
Intake Centerline:
 108
Firing Order:
 1-8-4-3-6-5-7-2
 
autoxcuda said:
I’m not feeling the OP has Head CC’ing tools. Maybe I’m wrong?

Well here are the cam specs....

I think you need a cam card with more specs than this to figure out cranking compression. But I don’t get a vibe this is going to bleed cyl psi. Others thoughts???

Year:
 1964 - 2003
Make:
 Chrysler

Engine:
 273, 340, 360

Camshaft Type:
 Hydraulic Roller
Basic RPM Range:
 1200 to 5700
Valve Lift Intake:
 .475
Valve Lift Exhaust:
 .500
Duration Intake:
 274
Duration Exhaust:
 278
Duration at 050 Intake:
 221
Duration at 050 Exhaust:
 225
Lobe Separation:
 112
Intake Centerline:
 108
Firing Order:
 1-8-4-3-6-5-7-2
Click to expand...

It's been fairly accurate in the past.

View attachment 1715748426

20210606_221738.jpg
 
Need a little help here. Not sure what to input for barometric pressure

1st one I left blank

2nd one I used 14.7:1

E6907994-02BC-4BF3-BB3E-3F86C3D84607.jpeg


764234AB-F3DD-46BB-ADC0-C292FA6D2ED8.jpeg
 
I always see the measurements in millibars. (News forecast, It’s always changing.) Can you enter in 29.99 for example?
 
rumblefish360 said:
Posting the actual cam specs is SUPER HELPFUL!
Posting part numbers is OK at best. Saying or describing what it actually is, is better. Example; your comp timing chain. You have one! Terrific! There are so many options to which one it is and I myself (and few others) will not look it up to know exactly what it is. No one wants to do the homework on answers you should have provided.

As far as what head to use, it would be the best one you can afford. Hands down! Maxx 171 SB Mopar (Sold in Pairs) - PROMAXX Performance Products
Though I say to make the stretch and get ether;
Shocker 185 Mopar CNC (Sold in Pairs) - PROMAXX Performance Products
Or the Trick Flow heads.
Click to expand...
Definitely looking at those promaxx heads they seem to be the best bang for the buck on the Mopar market
 
autoxcuda said:
I’m not feeling the OP has Head CC’ing tools. Maybe I’m wrong?

Well here are the cam specs....

I think you need a cam card with more specs than this to figure out cranking compression. But I don’t get a vibe this is going to bleed cyl psi. Others thoughts???

Year:
 1964 - 2003
Make:
 Chrysler

Engine:
 273, 340, 360

Camshaft Type:
 Hydraulic Roller
Basic RPM Range:
 1200 to 5700
Valve Lift Intake:
 .475
Valve Lift Exhaust:
 .500
Duration Intake:
 274
Duration Exhaust:
 278
Duration at 050 Intake:
 221
Duration at 050 Exhaust:
 225
Lobe Separation:
 112
Intake Centerline:
 108
Firing Order:
 1-8-4-3-6-5-7-2
Click to expand...
I seemed to have misplaced the cam card wherver that thing went is beyond me. And yeah you would be correct in saying I don't have cc tools for a head. I'm just looking to build a fun little 360 for my scamp!
 
MOPAROFFICIAL said:
Use a Melling m72, skip the high volume.
On the later blocks you need to look out for flashing in the lifter bore feeds.
Buy some promax heads. Don't waste money on speeddisaster or edlebroke.
If you need more, trick flows.
Click to expand...
I agree with you and thanks for the recommendation on the promaxx heads, seem to be decent. Just need to decide scat I beam or speed master hbeam rods now! As far as head CC's go my options are 65cc or 62cc from promaxx
 
Scat I-beams, all the way....they can handle anything that those stock heads can throw at them, and they are WAY lighter than H-beams which means the rotating assembly will be cheaper to balance (assuming you have light weight pistons).

For what its worth, I have Scat I-beams in my low 10 second stroker motor and they hold up just fine.
 
Here’s my inputs for cranking compression figuring a 66 cc head...

then the outputs

Will this run a 91 octane with no brainer tuning ??

D70082DE-D2B1-44D4-BFC1-90D29CAC5CC3.jpeg


24EB3B1E-3D9C-4E95-85F4-4102E6D6FE84.jpeg
 
flyfish said:
Scat I-beams, all the way....they can handle anything that those stock heads can throw at them, and they are WAY lighter than H-beams which means the rotating assembly will be cheaper to balance (assuming you have light weight pistons).

For what its worth, I have Scat I-beams in my low 10 second stroker motor and they hold up just fine.
Click to expand...
Thanks for the input on them scats, my machine shop said the same thing too on the scats basically they're bullet proof for street cars
 
Last edited:
Josshh70 said:
I agree with you and thanks for the recommendation on the promaxx heads, seem to be decent. Just need to decide scat I beam or speed master hbeam rods now! As far as head CC's go my options are 65cc or 62cc from promaxx
Click to expand...
I beam is a hair lighter than an h beam, on average.
I've run h beam, very strong, they're typically used for big torque motors or pulling. You can use either in something like this.
I beam would be fine.
They're closed chamber and can be massaged/softening larger.
 
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