Heads Help!

[tomswheels]

So I'm doing a lot of Autocrossing and want to maximize my HP/TQ per $$ on a LA 360 I have. I believe it's a 1975 360 that has been rebuilt, haven't had the heads off but engine looks very clean inside and runs well, feels like about 200HP and 300 ft/lb at the rear wheels... My question for you all is how to get the most out of my heads without a lot of $$, OR, should I be looking at another head option? Chinese aluminum heads are about $1000 assembled, that is the most I would like to spend, but can I get just as much flow and a nice 10-1 compression out of magnum heads or j heads or my smog heads for less $$? Opinions welcome, thanks in advance...

 

[OldmanRick]

Tom, I assume this is a street driven/pump gas car that you AutoX for some fun? Not knowing the total combo you have will hamper any suggestions, but as I see it, we can break this down to 3 individual mods and how the 1k would be best spent.....

1) Head flow
2) Compression
3) Camshaft selection

#1 & #2 can go hand in hand, but that may leave you lacking in the cam department? A set of KB pistons could get you a solid compression ratio, but the required machine work would certainly use up your budget?

From what I see at this point, I'd look into some mild port/bowl work and a good valve job with the existing heads.....maybe even a 2.02" intake valve along with that, plus a thin head gasket to get whatever compression increase you can? Along with that, I'd go right to a cam that will maximize your total combo. With some research, and with so many "shelf" cams available today, I'm sure you can find something superior to what you're running now. Also, there is always a custom grind from one of the good grinders that would fill any void if needed?

Like I said, that's my thoughts "for now" with only 1k to spend.....

 

[RustyRatRod]

Save some more money.

 

[AJ/FormS]

Where in the power band/rpm range, do you feel your engine is lacking?

 

[moper]

Save some more money.

x2. You can stick a mild cam in it, some 901-16 Comp springs, a set of standard retainers for the exhaust valves, and an intake/carb & have some fun like that. You're not going to repalce the heads to any real benefit for $1000. You'd have to do too much other stuff, costing more $$. How are the car's wheels & tires, brakes, and suspension? You will get more results in terms of autoX performance by upgrading those things first.

 

[rumblefish360]

With autoX, handling is certainly a priority!

Power wise, the cam should suite the course.
Head wise, like RRR said, save Mo-money! The Chinesse heads will require Mo-Money.

 

[tomswheels]

Thanks all of the above! The car has the full Hotchkis TVS kit, and it's handling well, need more front brake and HP. I like the torque the engine currently has down low, and don't want to lose a lot of torque so I'm thinking I don't want/need too radicle a cam. I was hoping some sort of cam and heads/ head work would help the most for the $$ spent. Having my smog heads re-done, what should I have done and what should I expect to pay? I'd like to get the smog holes filled, mild port work and springs as suggested above, a little milling for compression? Anything else? Thanks again in advance...

 

[AJ/FormS]

Do you have any knowledge of what cam is in there now?
Can you indicate or estimate at what rpms you engine spends the largest percentage of time.or where its weak.
Ive only ever autocrossed twice and that was on grass so it doesnt count. Sure was a blast though.And I would love to participate more often but its just not feasible for me. The nearest track(concrete) is 1.5 hours away.I do watch it on tv or Utube whenever I can.I love watching you guys.
One thing I have noticed is that the engines seem to spend a very significant amount of time powering through the midrange. It also seems that the engines are often heavily throttled,down low; as in babied to prevent wheelspin/slides. And they only seem to spend milliseconds at high rpm. So it seems to me that the engines need a broad smooth mid-range more than anything.
What is your opinion on that assessment?

Is/are your gear ratios optimized?

 

[tomswheels]

I don't but it feels torquey and runs out of breath about 4800 rpm. Would it be any advantage trying to run down swirl-ports?

 

[AJ/FormS]

Do you think you would be willing to give up some of that torqueyness for a bit more power after 4800. And how much higher do you think the power needs to go?

Are your gear ratios optimized?
Is your timing optimized?
What fuel is available?
What carb and intake are you running?
Do you have cranking compression numbers?

 

[tomswheels]

Do you think you would be willing to give up some of that torqueyness for a bit more power after 4800. And how much higher do you think the power needs to go?

Are your gear ratios optimized?
Is your timing optimized?
What fuel is available?
What carb and intake are you running?
Do you have cranking compression numbers?

I think I would give up some torque if I could move the usable RPM range up higher so that I have a wider usable band. I'd love to make MORE usable power between 3000 and 5800 or 6000 RPM. I'm in the process of switching from the not optimal A833 OD to a regular A833 with a 3:08 rear. Fuel sucks here, 91 octane at best. Car was dyno tuned so I think timing is good. Holley 575 Street Avenger with an Edlebrock performer (older). I don't have the compression numbers, but it seems like the short block is fairly freshly rebuilt...

 

[OldmanRick]

From what I see at this point, I'd look into some mild port/bowl work and a good valve job with the existing heads.....maybe even a 2.02" intake valve along with that, plus a thin head gasket to get whatever compression increase you can? Along with that, I'd go right to a cam that will maximize your total combo. With some research, and with so many "shelf" cams available today, I'm sure you can find something superior to what you're running now. Also, there is always a custom grind from one of the good grinders that would fill any void if needed?

At this point, i'm still sticking with the above paragraph from my post #2...

The fact that you want to go back to the "close" ratio trans does help with cam selection. Something in the 112/114LSA range with the proper duration will give you a nice flat curve in the range you're looking for. And as always, some decent lift with that cam timing will make the most power.

Most will think the Performer intake & smallish Holley would be a detriment, but I've seen similar combo's on 400" engines perform outstandingly.

As I said earlier, clean up the heads and cam that engine properly.....




Put a gun to my head for a off the shelf grind, and from what I think you're dealing with, I'd use this.....Keep in mind, Crower rpm specs are geared toward the torque curve. This cam will easily pull as high as you need it!

http://www.summitracing.com/parts/cro-31241/overview/make/dodge

 

[AJ/FormS]

Ummm Tom; Seems like? Please dont get your hackles up, but "seems like" is not quantifiable.I use it all the time because its an opinion and its hard to argue with an opinion.So then smart-alecs dont come around and want to start fights with me all the time.If I state an absolute, and theres any chance Im wrong, somebody with nothing better to do will call me to the mat in the blink of an eye. So I use the"seems like" catch all;a lot.
But when it comes to compression, we need quantifiable accurate numbers. Your engine(or any engine)will perform way different at 185psi, than at 120. And if youre only making 120, then a next larger cam will mostly make things worse. But if youre at 185, then you could go a size or two bigger and the top-end charge would pick up faster and harder than the torque loss at the bottom.So knowing the numbers helps in the decision making.Especially with a limited budget.If you have good numbers then the best bang for the buck goes to the cam.But if you have to bring the compression up first, it blows the budget in a hurry.Now, I "seem to" have noticed that youre antsy to either change heads or at least mod yours.But i"feel" that you cant build a house til the foundation is built, and so it is with engines.Throwing parts at it without knowing the specifics is probably the least bang for the buck.
Without taking the heads off and measuring stuff, theres only one way to get an idea of what you foundation looks like. And that would be the accurate compression numbers.
I 'feel", and "it seems like", OldmanRick knows his stuff.
------------
Now lets talk trannies. I would be interested in your thoughts as to the 3.09low.
It "seems like" to me that youre jumping ahead too fast.
Heres why; Lets say its cheaply possible to put 30 or 40 more hp into that engine, and extend the operating range to 6000rpm.Now that could demand a reduction in gearing(smaller number), not an increase(bigger number). So then you might be either going to a different rear gear, or be forced to shift into second. And then with the 3.09 low, a shift into second is waaay back in the basement; your Rs will fall to 62%.That would be a deep hole to try and climb out of.Better it would be to have a closer 1-2 ratio gear set(the 2.66 set), where the Rs fall to 72%. But best it would be to not have to shift at all.So if you have the optimal rear gear, the tranny ratio becomes moot.And the optimal rear gear cannot be selected til the engine pkg has been finalized.
Am I making any sense at all?

 

[moper]

I think if it was me I'd still minimize the expense on the existing heads. If the exhaust ports are still open, you're not running headers - correct? I would look at a small solid flat tappet cam that will give you decent area under the curve but not require big headwork os rpms. Buy a decent set of headers and have a good exhaust connected to them. Then buy some brakes. Then when you've maxxed that out (good move on the transmission BTW) you will have a decent platform to add some power to.

 

[Cudafever]

Moper stepped on something there, that i didn't catch. If you still have exhaust manifold on there.........SPEND YOUR MONEY ON GOOD QUALITY HEADERS. Headers are one of the few performance parts that don't still from peter to pay pal.

A header will give you more Torque and Horse Power threw the hole RPM range.

 

[Bakerlite]

Magnum heads , more comp and a cam to suit.
1.92"/1.625" MP stainless valves, straight 45*, these are a set of Dodge Truck Magnum iron heads:

LIFT----AS CAST
---------IN/EX
.100"--67.3/N/A
.200"--131.3/97.3
.300"--185.6/132.5
.400"--212.5/144.9
.450"--213.9/146.3
.500"--212.2/146.3
.550"--212.5/146.3
.600"--213.9/146.6
.650"--214.2/147.3
.700"--215.3/147.3

 

[tomswheels]

At this point, i'm still sticking with the above paragraph from my post #2...

The fact that you want to go back to the "close" ratio trans does help with cam selection. Something in the 112/114LSA range with the proper duration will give you a nice flat curve in the range you're looking for. And as always, some decent lift with that cam timing will make the most power.

Most will think the Performer intake & smallish Holley would be a detriment, but I've seen similar combo's on 400" engines perform outstandingly.

As I said earlier, clean up the heads and cam that engine properly.....




Put a gun to my head for a off the shelf grind, and from what I think you're dealing with, I'd use this.....Keep in mind, Crower rpm specs are geared toward the torque curve. This cam will easily pull as high as you need it!

http://www.summitracing.com/parts/cro-31241/overview/make/dodge

Perfect, thanks, this cam will be at the top of my list

Ummm Tom; Seems like? Please dont get your hackles up, but "seems like" is not quantifiable.I use it all the time because its an opinion and its hard to argue with an opinion.So then smart-alecs dont come around and want to start fights with me all the time.If I state an absolute, and theres any chance Im wrong, somebody with nothing better to do will call me to the mat in the blink of an eye. So I use the"seems like" catch all;a lot.
But when it comes to compression, we need quantifiable accurate numbers. Your engine(or any engine)will perform way different at 185psi, than at 120. And if youre only making 120, then a next larger cam will mostly make things worse. But if youre at 185, then you could go a size or two bigger and the top-end charge would pick up faster and harder than the torque loss at the bottom.So knowing the numbers helps in the decision making.Especially with a limited budget.If you have good numbers then the best bang for the buck goes to the cam.But if you have to bring the compression up first, it blows the budget in a hurry.Now, I "seem to" have noticed that youre antsy to either change heads or at least mod yours.But i"feel" that you cant build a house til the foundation is built, and so it is with engines.Throwing parts at it without knowing the specifics is probably the least bang for the buck.
Without taking the heads off and measuring stuff, theres only one way to get an idea of what you foundation looks like. And that would be the accurate compression numbers.
I 'feel", and "it seems like", OldmanRick knows his stuff.
------------
Now lets talk trannies. I would be interested in your thoughts as to the 3.09low.
It "seems like" to me that youre jumping ahead too fast.
Heres why; Lets say its cheaply possible to put 30 or 40 more hp into that engine, and extend the operating range to 6000rpm.Now that could demand a reduction in gearing(smaller number), not an increase(bigger number). So then you might be either going to a different rear gear, or be forced to shift into second. And then with the 3.09 low, a shift into second is waaay back in the basement; your Rs will fall to 62%.That would be a deep hole to try and climb out of.Better it would be to have a closer 1-2 ratio gear set(the 2.66 set), where the Rs fall to 72%. But best it would be to not have to shift at all.So if you have the optimal rear gear, the tranny ratio becomes moot.And the optimal rear gear cannot be selected til the engine pkg has been finalized.
Am I making any sense at all?

Gotcha, I'll get out and compression test it ASAP. The A833 OD is going out, the 2.66 first "normal" A833 is going in...

I think if it was me I'd still minimize the expense on the existing heads. If the exhaust ports are still open, you're not running headers - correct? I would look at a small solid flat tappet cam that will give you decent area under the curve but not require big headwork os rpms. Buy a decent set of headers and have a good exhaust connected to them. Then buy some brakes. Then when you've maxxed that out (good move on the transmission BTW) you will have a decent platform to add some power to.

Moper stepped on something there, that i didn't catch. If you still have exhaust manifold on there.........SPEND YOUR MONEY ON GOOD QUALITY HEADERS. Headers are one of the few performance parts that don't still from peter to pay pal.

A header will give you more Torque and Horse Power threw the hole RPM range.

Sorry forgot to mention TTI shortys. They were the only ones I could make fit with the factory ZBar...

Magnum heads , more comp and a cam to suit.
1.92"/1.625" MP stainless valves, straight 45*, these are a set of Dodge Truck Magnum iron heads:

LIFT----AS CAST
---------IN/EX
.100"--67.3/N/A
.200"--131.3/97.3
.300"--185.6/132.5
.400"--212.5/144.9
.450"--213.9/146.3
.500"--212.2/146.3
.550"--212.5/146.3
.600"--213.9/146.6
.650"--214.2/147.3
.700"--215.3/147.3

Where is a good place to buy reconditioned or new Magnum heads?

Thanks everyone!

 

[AJ/FormS]

Doh! I miss-read youre post #11; re the "3.08 rear"And jumped to the conclusion that it was a misprint of "3.09 gear", and that you were therefore installing a 3.09 low trans. I am not familiar with any 3.08 Mopar rear gear. Yeah so youre deff on the right track getting rid of the O/D trans.
-------
A 3.08, and 2.66low will get you 58ish MPH @6000 with tires of 84" rollout.But I bet you knew that.The 3.09low would need a 2.76 rear to get 56MPH at 6000. Heh-heh

 

[moper]

Don't bother with reconditioned/used. Buy a set of EQ Magnums and have them assembled. Keep the cam choice conservative and remember the Magnum uses a 1.6 rocker so you have to factor in the extra ratio/lift for spring choice. You will also need to buy Magnum rockers and pivots, and new pushrods (should be measured - don't trust factory length). This approach will need more than the $1K budget but will be worth it.

 

[roccodart440]

My question for you all is how to get the most out of my heads without a lot of $$, OR, should I be looking at another head option? Chinese aluminum heads are about $1000 assembled, that is the most I would like to spend, but can I get just as much flow and a nice 10-1 compression out of magnum heads or j heads or my smog heads for less $$? Opinions welcome, thanks in advance...

When I had my iron heads done maybe 15 years ago it cost me about 1200 bucks for porting, new valves etc..

If you get an OOTB head I'd at least have a shop check them out before you run them.

In regards to where they are made? I don't know which heads are made where. I've run the eddy heads with decent success.