Choosing a 360

[74Scamp]

Hi guys,
New member here but I’ve been reading through the forum for awhile and learned lots of good info. Quick scenario; I have my 1974 Scamp that’s getting a 408 stroker in it. I’m wanting to get +500 hp out of the engine.
The further I read into the info the more I sorta got lost after awhile. My buddy has a 91’ LA 360 that he’d sell to me. Would it be safe to say that’s still a good year of the LA’s to use for my project or would I be looking around again for a older engine still?

 

[jas0162]

91 was a good year. It came with a hydraulic roller cam and the 308 heads. A flat tappet cam will go right in there if you get different pushrods.

 

[Abodybomber]

Block year ,doesn't really matter.. a standard 4 inch bore to go .030 over ,squared up, applies for endurance ,helps more than anything here A forged piston assembly, would be better , for everything here..
Have it balanced professionally. Stock heads don't work here ,need at least 250 intake flow ,either professionally ported irons ,or a reworked Edelbrock.? No they do not flow those numbers out of the box ,not even close.
Cam numbers? A tighter lobe center gets better ,as the compression nears 10 to 1..
285 Xehl Comp Cams for hydraulic flat tappet , solid lifters ? somewhere around a 240-250 @ 050 on a 108i-110 lobe center, will peak ...5500-5800..
Expect chassis tuning ,or break drive chassis at will...

 

[74Scamp]

Block year ,doesn't really matter.. a standard 4 inch bore to go .030 over ,squared up, applies for endurance ,helps more than anything here A forged piston assembly, would be better , for everything here..
Have it balanced professionally. Stock heads don't work here ,need at least 250 intake flow ,either professionally ported irons ,or a reworked Edelbrock.? No they do not flow those numbers out of the box ,not even close.
Cam numbers? A tighter lobe center gets better ,as the compression nears 10 to 1..
285 Xehl Comp Cams for hydraulic flat tappet , solid lifters ? somewhere around a 240-250 @ 050 on a 108i-110 lobe center, will peak ...5500-5800..
Expect chassis tuning ,or break drive chassis at will...

I have a few buddies in my area that have 408’s with high hp so I was going to somewhat follow their recipe. I know that heads are a big priority for hitting my goal aside from a good cam to match. Either was gunna go with some really well ported J heads or if I find a good deal on some edelbrocks I’ll have them ported as well.

I figured too I’d be pushing the factory chassis but I’ll address that along with the engine build. Anywho I appreciate the info fellas, I’ll be buying this engine then.

 

[Wyrmrider]

500 hp without some head work is tough
cam choice XE285HL should work but depends on your gears and converter and what rpm range you are looking for
but why switch from a HR?
this piston
KB Hyper Piston - Chry 408 Rod 6.123 Quench Head 23.5cc 2V [KB356] - $462.70 : United Engine & Machine Co. Incorporated, Performance Pistons
IDK of any forged versions for open chamber head J head and 308's would be a better starting place in the first place
I would not sink money into guides and ex seats and porting on J heads unless this is a "stealth" build, matching number kind of build
so use the hyper piston above with X J 308 heads
get a custom forged piston made to these or similar specs to get the CR you want with the J, X, 308
or
use closed chamber heads- lots of piston choices
Chrysler : United Engine & Machine Co. Incorporated, Performance Pistons
just for samples, click on the piston pic to get details- some are for magnum blocks
only go .020 if you have a choice- your block will clean up
let's get a CR target and what gas b 4 going further
1992 and up blocks with crank clearance to deck of 9.585. Pre-1992 blocks have crank clearance to deck of 9.599.
so you can deck a LA block and use magnum pistons (with closed chamber heads) or let magnum stick out of the block like a 340
plenty of ways to get the cr you want
just do not use flat top or dished flat top pistons with LS J or X or 308 heads

 

[3406pk]

If that 91 360 is roller cam, get a hughes roller cam if you want some hp with good reliability.

 

[skrews]

91 was IMO one of the best years. From what I've seen the preMagnum roller cam blocks are much better castings (materials and lless core shift), and have much better factory machining than the earlier stuff.

500 HP really won't tax any factory block, unless one of the cylinder walls has a thin spot.

 

[RustyRatRod]

There's not a bad year for the 360.

 

[rumblefish360]

Very true. Even better if it hasn’t been over bored yet. I myself like the later year roller blocks better. But any 360 falling into my lap is good to go. Get your buddies block and run with it.

You mentioned porting Edelbrock heads. For the cost, of you start comparing prices vs performance, you may want to consider Edelbrocks Victor head. It will flow better than a ported RPM head.

Just food for thought....

 

[74Scamp]

500 hp without some head work is tough
cam choice XE285HL should work but depends on your gears and converter and what rpm range you are looking for
but why switch from a HR?
this piston
KB Hyper Piston - Chry 408 Rod 6.123 Quench Head 23.5cc 2V [KB356] - $462.70 : United Engine & Machine Co. Incorporated, Performance Pistons
IDK of any forged versions for open chamber head J head and 308's would be a better starting place in the first place
I would not sink money into guides and ex seats and porting on J heads unless this is a "stealth" build, matching number kind of build
so use the hyper piston above with X J 308 heads
get a custom forged piston made to these or similar specs to get the CR you want with the J, X, 308
or
use closed chamber heads- lots of piston choices
Chrysler : United Engine & Machine Co. Incorporated, Performance Pistons
just for samples, click on the piston pic to get details- some are for magnum blocks
only go .020 if you have a choice- your block will clean up
let's get a CR target and what gas b 4 going further
1992 and up blocks with crank clearance to deck of 9.585. Pre-1992 blocks have crank clearance to deck of 9.599.
so you can deck a LA block and use magnum pistons (with closed chamber heads) or let magnum stick out of the block like a 340
plenty of ways to get the cr you want
just do not use flat top or dished flat top pistons with LS J or X or 308 heads

Well thanks for all of that info! I know I’ll be needing some really well worked over heads for 500 or more hp. I plan on running a 91 pump gas, it’s the highest oct you can get in my state. Although I can buy race gas from certain shops but that’ll be a hassle. I figured a streetable CR like 10.5:1 would be a good choice. I haven’t decided if I stick with an auto or put a manual in the car. If I stay w/ auto I’d do a 3,500-3,800 stall and either 3.55 or 3.91 in the rear. RPM range would be 6,500-7,000.

 

[74Scamp]

Very true. Even better if it hasn’t been over bored yet. I myself like the later year roller blocks better. But any 360 falling into my lap is good to go. Get your buddies block and run with it.

You mentioned porting Edelbrock heads. For the cost, of you start comparing prices vs performance, you may want to consider Edelbrocks Victor head. It will flow better than a ported RPM head.

Just food for thought....

I’ve just seen enough guys running Edelbrock heads that liked them but I’m not stuck on them either. I’m keeping an open mind when it’ll come to picking heads, as far as cost vs gains will be. My one other bigger choice, and I need to look into this, is if I go with a flat tappet or go to a hydraulic roller cam, then from there pick a cam.

 

[rumblefish360]

I’ve just seen enough guys running Edelbrock heads that liked them but I’m not stuck on them either. I’m keeping an open mind when it’ll come to picking heads, as far as cost vs gains will be. My one other bigger choice, and I need to look into this, is if I go with a flat tappet or go to a hydraulic roller cam, then from there pick a cam.

Roger that my man. Good idea to keep the mind open. Many here will tell you it is hard to get enough head on top of a stroker.
IMO, The cam should be a solid lifter cam, FLT or roller. Once you know the heads port flow capability, look for a cam that takes advantage (lift) of the heads air flowing ability in the duration that fits the rpm range you want to perform in.

Good luck with your build!

 

[flyfish]

If you are looking for 500+ hp, go over to the race forum and look at the "post your 10 second combo" thread. Lots of good info in there (including my pump gas build)...those combo's are about 500hp, give or take.

Post your 10 second combo

........get ready to open your wallet up REAL WIDE...lol.

 

[74Scamp]

If you are looking for 500+ hp, go over to the race forum and look at the "post your 10 second combo" thread. Lots of good info in there (including my pump gas build)...those combo's are about 500hp, give or take.

Post your 10 second combo

........get ready to open your wallet up REAL WIDE...lol.

I saw a few guys in there running 10’s with 408’s. Few are close to what I want. The pocket book wouldn’t feel any better if I want with a 400 BB stroker (there’s a local 400 I can snag for $250 and it’s tempting). Thanks for that thread tho, I’ll keep looking through more build combos

 

[moper]

Is there a reason for the 500hp target? An ET, bragging rights at the cruise night? It's pretty easy to get to the 450 level with little more than bolt on parts and a performance valve job on your 308 heads. I won't run a hyper piston in the 4" engines. I have used the quench dished version pistons keeping the static closer to 9.8:1 for good pump gas reliability and open chambers. That engine makes around 450hp, maybe a tad more but the heads were taken further than just the "good valve job" stage to get there with a moderate sized flat tappet. The '91 block will be a more consistently cast block, and it has the bosses for the hydraulic roller cams. I'd use that one. Sonic test it to make sure it's not core shifted. Get a 4" crank, Eagle SIR rods, SRP forged pistons, internally balance it, prep the block (blueprint it, basically), and have the heads gone through. Budget would need to be around $8500, maybe a little more depending on the parts choices and your local labor costs for a good performance shop to machine the stuff. Assembly and dyno/breaking would be more.

 

[74Scamp]

Is there a reason for the 500hp target? An ET, bragging rights at the cruise night? It's pretty easy to get to the 450 level with little more than bolt on parts and a performance valve job on your 308 heads. I won't run a hyper piston in the 4" engines. I have used the quench dished version pistons keeping the static closer to 9.8:1 for good pump gas reliability and open chambers. That engine makes around 450hp, maybe a tad more but the heads were taken further than just the "good valve job" stage to get there with a moderate sized flat tappet. The '91 block will be a more consistently cast block, and it has the bosses for the hydraulic roller cams. I'd use that one. Sonic test it to make sure it's not core shifted. Get a 4" crank, Eagle SIR rods, SRP forged pistons, internally balance it, prep the block (blueprint it, basically), and have the heads gone through. Budget would need to be around $8500, maybe a little more depending on the parts choices and your local labor costs for a good performance shop to machine the stuff. Assembly and dyno/breaking would be more.

500 hp is just a goal that I’d like to so I have enough hp without having to redo everything, learned that before. Like I’ve posted it’ll be a street car more than anything. If I get close to 500 crank I’ll be happy still. Budget still rules over everything. I can do the engine rebuilding myself but any machine work will have to be a a shop for sure.

 

[Wyrmrider]

As MOPER says 450 is easy 500 is a big jump
read his post above again
Moper
I do not see any SRP pistons OPTIMISED for open chamber heads
500 gets even tougher with open chamber 408 X J etc heads- would never do it
"street car more than anything"
"quench dished version pistons keeping the static closer to 9.8:1 for good pump gas reliability and open chambers. That engine makes around 450hp, maybe a tad more but the heads were taken further than just the "good valve job" stage to get there with a moderate sized flat tappet. The '91 block will be a more consistently cast block, and it has the bosses for the hydraulic roller cams. I'd use that one. Sonic test it to make sure it's not core shifted. Get a 4" crank, Eagle SIR rods, SRP forged pistons, internally balance it, prep the block"
but for a street build the KB's will be fine
still not a short compression height and a rod length the sbc buys would cry for
as you say compression limited by the gas and power is in the heads

 

[moper]

That's because as usual you are looking for "optimized" and overthinking details that don't need it. That's a common occurrence on this board of late...lol. You and I definitely do not approach solutions the same way and your comments are hard to follow because of your writing style. Not meant as a cut, just observation. Post your own ideas and why, in clearly written, grammatically reasonable sentences and the OP can choose.
He needs (in my opinion) a forged piston, with a dish. Blueprinting includes square decking it, and the compression can be set via that and the chamber size and a piston with a big dish. Hypers are great pistons, but a missed shift or broken driveline puts the mean piston speed too high IMO for them in any stroked application. I won't run them in that application. Or recommend them for it. Period.
Any factory 340/360 head can make upwards of 480hp with some gasket matching, light blending, the right performance parts, and a high quality performance valve job. 500+ is a stretch without paying a shitload for good porting, which makes using any factory head a waste of money anyway. If you want 500hp at the crank, spend on better heads and make better use of the quench dish forged pistons.
Street car. Simple street build. No need for anything fancy or overthinking.

 

[Wyrmrider]

No need for overthinking except he wants 500 HP not 450
Street car build if for street torque curve not shooting for Max HP, especially with a stroker
I'd go heads and hyper pistons but with heads then custom forged pistons are not necessary
I would not build with flat top dished and open chamber heads- been there- done that
too many problems with broken pistons and rings when I do not have control of the timing or the fuel
tight quench is much more tolerant of fuel and timing and load
cheers
moper
ps I'm dyslexic just treat each line like a bullet point- I'm not writing a novel
and I get (even more) confused with dense prose

 

[74Scamp]

I do understand Wyrmrider’s posts so no biggie there. I do have one question. I am buying my buddy’s 360 but it’s out of a Ram. Do I need to find some 360 a body engine mounts or can I use the truck mounts?

 

[rumblefish360]

You’ll need to find car mounts. EZ pee-zeee.

It is an LA 360?

 

[74Scamp]

I pretty much figured I’d be looking for car mounta but I figured I’d ask. It’s a LA 360.

 

[74Scamp]

Trans-Dapt Performance Engine Swap Motor Mounts 4695
Would that be a good kit to get then or is there a better option? (No JY around men has a 360 a body).

 

[rumblefish360]

Trans-Dapt Performance Engine Swap Motor Mounts 4695
Would that be a good kit to get then or is there a better option? (No JY around men has a 360 a body).

No. that is only good until 1972. So, unless you have an older '72 and down K frame in your '74, it is a no go.
Go here instead; Schumacher Creative Services

 

[74Scamp]

No. that is only good until 1972. So, unless you have an older '72 and down K frame in your '74, it is a no go.
Go here instead; Schumacher Creative Services

Dang it..still learning what years work for others. Jeez them schumachers have a price tag on them lol I’ll do some searching for others but if not I’ll go for those ones. Thanks sir!