97 360 mag valvetrain ?s

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oldcarnut

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ive got a 97 360 magnum that i aquired in a trade , here are some specs:

30 over 9.5:1 pistons
comp thmpr cam hyd rllr, .513 grss vlve lift(intake) , .498 ex p/n206009
knockoff airgap intake
750 eddy carb
mallory unilite 3767901 (mech adv)
904 w/ mild convertor
3:55 gear
car is 70 dart

this is my concern.... head castings are new but all stock hardware was reused . The valve springs are my main concern . I spoke with comp cams & they said the springs definetly need to be changed . im not concerned about rockers but would it be a considerable benefit to go with a non adj alum rocker like the harland sharp pieces , the original dist gear was also re used , should this be changed as well ? opinions please ....
 
forgot to mention , the motor has not been fired yet.
 
The problem with NOT using adjustable rockers is the camshaft base circle. If it is ground smaller than stock.....and I believe they are, because no one that I am aware of has Magnum blanks, then you'll need longer pushrods. Simple enough to check since the engine has not busted off yet. It's not true in all cases, but better to be safe than sorry. Know what I mean vern? And yes, change the springs out.
 
The springs should definitely be changed. I would contact Hughes engines about replacements unless Comp has something they know for sure will work.

As far as benefit with the Harland Sharp pieces, it all depends on what you're after. My car went 11.70 and turned 6300 many times with the stock rockers with no ill effect.

I recently switched to the Harland Sharp. Maybe there are a couple of horsepower there, but the stock stuff can put up with a lot.

If you're after horsepower, the easiest thing to do would be throw that knockoff intake in a lake and get the real Edelbrock unit.

EDIT: Strokerscamp is likely right about the pushrod length. I have a comp custom grind that still has the oil holes and snout for the fuel pump eccentric and it required a .050 longer pushrod than stock.

Good luck with it!
 
thanx guys , are the knock off intakes really that bad ?
 
Yes, they are horrible. There is a lot more to an intake manifold than making 8 tubes and attaching them to a plenum. The Chinese either do not know this, or do not care. Nevermind the low grade aluminum and ridiculously irregular castings.

I've had that intake, the Magnum RPM intake and the LA RPM intake (which is the best of the three and what I currently run-my heads are drilled for LA style intakes).

LA RPM vs knockoff, I'm betting to be about 15-20hp on my motor.
 
oldcarnut said:
thanx guys , are the knock off intakes really that bad ?
Click to expand...

I've heard nothing but good stuff about them. I have one and plan to use it. If there are bad things going around about them, this is the first I've heard. LXGuy is a good member though and I don't think he'd blurt somethin out for the hell of it. I wouldn't mind him expoundin on that one myself. Cause I've held the two side by side....even measured ports and they are pretty identical. Maybe I got a good one?
 
Well, I am trying to dig up pics for this, but am at work. Perhaps you got a good one and perhaps I got a bad one. All of my opinions are based on my experiences with one intake.

It should be noted however, that they sell these types of intakes for Ford and Chevy too, and it is pretty easy to find various anecdotes from people switching to the Edelbrock from the Pro Products and picking up ET/HP with those cars too.

There are a lot of problems with the chinese intake. It is not a direct clone of the air gap as a superficial examination would indicate.

The runners and the plenum on the edelbrock are actually larger. Further, the runners on the Chinese have almost no taper at all. Comparing the shape of the runner in addition to the size, it becomes obvious that Edelbrock does theirs the way they do for a reason, and the Chinese are just throwing aluminum in a casting mold.

The ports on the intake I had were horrible. The opening sizes were radically different and they were not even aligned [EDIT}vertically!

I checked gasket alignment (these are the pics I am hunting). I did this by placing the gasket on the cylinder head, then installing the intake, torquing it in place, scribing the exposed portion of the gasket, removing the intake and placing the gasket against the intake while lining it up with the scribe marks.

The Edelbrocks were on the money for alignment when checked in this fashion. The Chinese was off badly. A couple of ports were much too high. Most notably the ports on one side at the rear were so misaligned that the divider between the ports was off horizontally about 1/16" - 1/8". Of course, this means there was precious little gasket available to separate the ports (hello vacuum leak), and that once installed there would be a significant amount of the divider blocking the intake tract.

This problem cannot be corrected with port matching!! Nevermind the fact of making it clear the people casting these are pure clown shoes.
 
Here's the only pic I can dig up at work. It is a comparison of the port on the Magnum air gap and the Pro Products.

IMG_1331-1.jpg


There are a number of reasons why this is not a good photo and they are all my fault. the ports appear smaller than they are on the Eddy because it is further away.

Check out how the Edlebrock openings are uniform and parallel, vs. the PP. Also check the machining around the bolt holes. Sheesh!

Further, vertical port misalignment on the Pro Products is deemphasized by the viewing angle. the port on the left is much higher than the one on the right.
 
can the valve springs be replaced w/o taking heads off ? or should i just remove heads
 
I gotchya. I knew you weren't blowin our skirt up. I musta got a decent one, because that's the first thing I did when I got it. Measure and inspect all the ports. They look good. Thanks for all the info on them. Without a doubt, I am certain you're right. Especially after seeing the comparison. Thanks.
 
oldcarnut said:
can the valve springs be replaced w/o taking heads off ? or should i just remove heads
Click to expand...

The valve springs can be replaced without removing the heads.

You need one of these:
http://www.summitracing.com/parts/OTC-4573/

And some way to put air to the cylinder to keep the valves from falling in when the spring and locks are removed.

I use something like this:
http://www.summitracing.com/parts/WMR-W84003/


I have a feeling Hughes would recommend their 1110 spring, and it would work with the compressor above. The crazy race springs take a little more umph which is a pain on pedestal mount heads, but you shouldn't have that problem.
 
Make sure to rotate the crank so the piston is at TDC of each cylinder when you replace the springs. If you bump the valves hard enough, even with air....if you don't have the piston up in that cylinder the valve will fall into the cylinder. That would suck.
 
thanx for link lxguy , yeah the 1110 looks like it would be just fine
 
For springs, I went to K & S performance.

http://www.monicattichrysler.com/co..._listCategoriesAndProducts.asp?idCategory=277

Scroll down to the bottom of that page.

I run a .508" purple cam in my magnum 360 which comes out to .543" lift @ 1.6 rocker ratio. I actually BROKE a stock, stamped steel rocker arm (tore it in half) with that set up. So I went to Crane roller tip rocker arms and the 5/16" to 3/8" rocker stud conversion kit and the MP P4876062 spring and it revvs higher and quicker. Really a nice valve trane set up and it's not too expensive either.

http://www.summitracing.com/parts/CRN-36655-16/

http://www.summitracing.com/parts/CRN-11746-16/
 
a1972dartswinge said:
For springs, I went to K & S performance.

http://www.monicattichrysler.com/co..._listCategoriesAndProducts.asp?idCategory=277

Scroll down to the bottom of that page.

I run a .508" purple cam in my magnum 360 which comes out to .543" lift @ 1.6 rocker ratio. I actually BROKE a stock, stamped steel rocker arm (tore it in half) with that set up. So I went to Crane roller tip rocker arms and the 5/16" to 3/8" rocker stud conversion kit and the MP P4876062 spring and it revvs higher and quicker. Really a nice valve trane set up and it's not too expensive either.

http://www.summitracing.com/parts/CRN-36655-16/

http://www.summitracing.com/parts/CRN-11746-16/
Click to expand...


I saw a post from a guy somewhere where he had used Oldsmobile rocker guide plates to really tighten up on the side to side pushrod movement on the 3/8 conversion to roller rocker if you had the studs only, or if the kit you buy had no replacement guides,
 
a1972dartswinge said:
Do Hughes 1110 springs work with Magnum Heads?
Click to expand...


Yup they sure do. I have some on my Magnum heads on the 318 I just put together.

LXGuy: I went and double checked my intake before I bolted it on tonight and it actually looks extremely good. Ports aligned straight and all are very symetrical. I musta got lucky.
 
X2, Stroker on the intake.The ports lined up nicely.Plenum was rough,so I dropped the plenum divider 1/2" and radiused and smoothed it all.
 
while im @ it do i need to address the issue of stock timing chain or should it be changed to double roller ?
 
I would highly recommend getting as good a timing chain as the budget allows. I also recommend a tensioner.

My Magnum engine (and pretty much all small block Mopars) stretch timing chains with a quickness.
 
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