chrysler 360 / 408 combos

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Keith Morganstein
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chrysler 360 / 408 combos

Post by Keith Morganstein »

When it comes to Mopar small blocks , I am not very experienced past a basic rebuild. I need some help on this. I did some internet research, but it's hard to sort that out.

I'm trying to help a customer with a chrysler 360/408 combo. The customer had a 340 that grenaded, stock rod broke in half. He has 340 heads that were ported. He took them to a head porter and the guy put them on his bench and claims they flow about as good as a stock set of edelbrock peformers. The heads may not be worth using as they are quite worn and partially damaged by the failure. Also the 340 had a big ugly dome to make compression and that's not how I like to go. I much prefer flat top pistons and an appropriately sized chamber.

The block he wants to use is a 1991 hydraulic roller block. Actually a NOS Short Block assy w/std bore. I am not sure what fits with these blocks, how good they are, what cams you can run etc... I suspect the hydraulic roller is heavy and not suited for RPM's. I see very few aftermaket hyd rollers for this engine.

The customer might be satisfied with 500hp and would love to be at 600hp.
He just trailers to the track to test and tune for fun and a low E.T.

I'm trying to figure out what it takes to get there. Everything is worth looking at now and then we'll have to see what the customer really wants to spend. I assume the stock rotator is good for only 400-450 hp with minor upgrades. Customer is considering a 408 stroker kit and there is a few options there.

There are quite a few heads from Edelbrock, Indy and Mopar. it's very unclear to me what fits with what kind of valve train, intake and header.

I've discussed the heads briefly with Mikes Porting (High VE) and it seems like a highly worked set of edelbrock performers may do.

I would like to know more about the options, including heads, block and rotating assy.

Thanks!
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Re: chrysler 360 / 408 combos

Post by automotive breath »

Max,
I recently had a set of 340X heads in my shop. I looked at the heads, especially the weird exhaust port shape; it's like nothing I have ever seen. In the car with a mild porting, a 360, a huge dome and giant roller cam it's very impressive, the heads make power. I can’t see how by looking at them.

The people at our trace that want to go real fast with the small block mopar run the Indy heads.
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Post by ou812 »

I use W2 heads on my 360 and my car goes 10.50's at 126. I'm using stock rods, stock crank, stock block, flattappet cam, 12.25 compression and 950HP carb. With a roller, light weight rotating components and more compression my car should run low 10's to flat 10. Car with me weights 3300lbs.
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Post by F1Fever »

I have a friend that just built a 408. I don't have all the specs but here's what I do have:
4.030 bore
Performer heads ported/milled to 60 cc - 270 cfm @ 650"
very small dome, 13,5:1
solid roller 263/270@050 106 lobe sep
6.123 rods
He tried a multilayer head gasket but there were no oil holes in it for the valve train, so watch that aspect.

Personally I'm not sure how the heads can flow that much either, there is severe pushrod pinch in the intake ports and the exhaust just looks odd to me. 3350lb 67 cuda, hopefully he will get some times in the next week or two.
I was no longer driving the car consciously. I was driving it by a kind of instinct, only I was in a different dimension.
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Post by Mentally Impaired »

I'd suggest a search on the race forum at:

www.moparts.com

However, IMO the search feature there is POO POO

There is some head flow info here: http://www.moparts.com/Tech/Archive/smallblock.html
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Post by highVE »

Keith,

Those edelbrocks i did on that 340 stroker deal flowed 288@.650" the end exhaust ports moved 230@.650" and the middle ports were down around 218 if memory serves me right.
Mike Theroux
www.mikesportingservice.net

There is never enough time!!
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Post by Keith Morganstein »

the crash course continues. I went to moparts.com but haven't received the login email to ask questions and search. Spent plenty of time surfing their site and the internet instead of working :roll:


Unsure of the offerings of many suppliers like Mopar Parts with their variety of magnum, commando and other heads. looks like the W2 head is to chrysler as the iron Bowtie is to chevy. But the w2 requires all different valvetrain, intake and headers? ](*,)

I don't think the customer will go $3,500 for the indy 360 head kit.

Maybe it's just looks familiar, but I'm interested in the newer Edelbrock performer magnum head w/57cc chamber. Seems to be an improvement over the ealier performer. That head would yield approx 11.66 :1 on a 360 and 12:91 on a 408 w/flat tops.

If with some work the head does a quality 290-300 cfm, it should make the required power. It uses a chevy style valve train that oils through the pushrod. Any experience with these?


The block has hydraulic rollers.
What retrofits in these blocks?
Mechanical flat tappet?
mechanical roller?
Is the hydraulic roller of any performace use in these engines?
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Post by LA_Spec »

Hi Keith. I would like to offer some insight to your thread. Your '91 block will probably be OK at the power level you describe, but I wouldn't go any further without filling it and mabye using a main girdle. If it has a std. bore then in order to do a 408 you will have to bore .030" over, as a 360 begins life with a 4"bore. The cheapest method of making the 408ci is with Mopars nodular iron 4" stroke crank. It is easily up to the task. Just about all the piston manufacturers have off the shelf pistons whether they be forged or hyperuetectic. You can get flat top or dish depending on the targeted compression ratio.


The big cam companies like Crane or Comp have just started producing some decent hydraulic roller stuff. In my opinion, I would scrap the factory hydraulic roller in favor of a solid flat tappet, or a solid roller if the customer is willing to spend a little more. They also make drop in solid roller lifters as well. If you decide to go flat tappet then Comp makes some really wicked lobe profiles they call the MM series. They are dedicated to the Mopar's .904 lifter, and the rates are about as fast as any other solid flat tappet I've ever seen. This would be the cheapest route while still easily accomodating your power level.


Now on to the cylinder heads. I find it hard to beat either of the Edelbrock castings because of their simplicity. Neither requires any special valvetrain, intakes, or headers. Although, the standard RPMs use stock style shaft rockers, and the magnums use a SB Chev style stud rocker. Edelbrock just recently released a killer looking Super Victor single plane for the standard style RPMs as well. They only build a Performer RPM for the Magnums as far as I know. Mopar makes a decent magnum single plane though. The magnums use a vertical style bolt similar to a Vortec Chev. These heads will surely need some port work though, as out of the box they are probably only good for 500-525hp in a maximum effort application. Mopar's W-2 is downright phenomenal when ported right. I've seen peak flow numbers hovering around 320cfm, and 300cfm is easy even with a 2.02 valve. That's pretty stout considering it is a cast iron head originally designed in the 70s, and its enough to surpass the limits of the stock block. Since then there have been many variables in chamber design and castings. They are an oval intake port that requires a W-2 dedicated manifold. Headers are special too, requiring adapter plates, except the later castings that were drilled for the dual pattern. They come in two basic configurations, race and econo. They are basically the same head except the econo has cast in rocker pedastals and the race heads have milled off pedastals necessitating special offset stands and shafts. The real problem is Mopar just recently discontinued the casting, but finding used parts for them is still relatively easy since they have been made for so many years. If going this route I would search for the long valve version of the econo head as the rocker setup is a little cheaper. Stay away from the later race style heads made for the 48* blocks, as they won't easliy work on your stock 59* block. Mopar also built a W-5, which is a rectangle port aluminum head that uses W-2 rocker gear and headers. They require a W-5 intake though. I would stay away from them as the earlier castings had some problems, and frankly they are pretty hard to find anymore. The Indy's are a nice head but like you said are too expensive, so we'll forget about them. Indy did make a specially machined Edelbrock head. They took partially finished castings and relocated the pushrod hole allowing a greater cross section at the pushrod pinch. Similar to the idea of the offset rocker on the W-2. They too need offset rockers and are about $2200 for the pair and Indy claims 295 cfm peak flow. Your probably better off with some standard Edelbrock heads with porting, as Mike has pointed out that his are peaked at just about 290. One more thing with the Edelbrock magnums. If you use them you will have to convert to pushrod oiling since the '91 block oils through the head and into the rocker shafts.


Hopefully I didn't write too much at one time, so you can digest some of the info. :lol: If anything it should help get you on the right track.

Lastly, you really need to check out Ryan Johnson's website "shadydellspeedshop.com". I consider myself to be knowledgable with small block mopars, hence the name LA Specialties, but Ryan probably has more experience with them than anyone on the planet. His site has everything there is to know about small block mopar cylinder heads, from stock castings to exotics like the W9RP. Every head he posts on there has detailed pictures and flow numbers. Lots of other great tech too. I could go on for hours, but I have to go. I'll be watching this thread so I can help out some more if you need it.

P.S. I'm not here to be a salesman or make a dollar, but I do have some parts I would be willing to sell if you would be interested. Email or PM me and we could go from there. Thanks
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Post by Keith Morganstein »

ou812 wrote:I use W2 heads on my 360 and my car goes 10.50's at 126. I'm using stock rods, stock crank, stock block, flattappet cam, 12.25 compression and 950HP carb. With a roller, light weight rotating components and more compression my car should run low 10's to flat 10. Car with me weights 3300lbs.
Brian
Brian (ou812) - Your 360 rotator assy. What prep was done for that power level? What pistons are you using, what balance?
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Post by Keith Morganstein »

Well, my thoughts are starting to come together a bit. Thanks for the help so far.

BTW, never too much info to digest here, but a google search...

Also, it would be good for my business to do well on this one, customer has a lot of friends in the local mopar clubs.

I'm leaning torward the Edelbrock magnum performer as the likely head choice.
This is for all the reasons as cited by LA_Spec and others esp. simplicity, availibilty, power and cost. (unless we run into a good package deal like a worked W2 set up).

Still haven't decided on stroker or not, but ou812's combo probably would be enough without stroking it.

Very likely use solid lifters, but will go roller if budget allows

Always more questions:

Can other intakes be redrilled or spaced to work well with magnum style heads?

The drop in roller lifters, are they tie bar or do they use the hyd roller guides?

Any advantage to using a later magnum block?
(The customer has one of them too)

Looked at stroker assy's from both ohio crank and competition products. Any reccomedations or other sources?

I am at a pretty good dicount with my warehouse, but I'm not sure how much chrysler they do.

What are the good strong light rods? (best balance of quality, weight and cost)

I see the mopar rod is way stronger than a stock chevy, but the customer just broke one and is a little shy about trying that again. I may reccomend them, but...


Thanks!
Last edited by Keith Morganstein on Sun Jul 23, 2006 12:44 pm, edited 1 time in total.
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Post by Mentally Impaired »

Max Effort wrote:
Can other intakes be redrilled or spaced to work well with magnum style heads?

Sort of, there used to be a loaner "Jig" available from a member on Moparts that you rented. It allowed the Magnum heads to be redrilled for LA intake manifolds.
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Post by ROGUE GTS »

Rather than chase your tail just call Ryan @ shady dell speed shop. He's pretty much the man on all things SB Mopar related.


What kind of budget does this guy have? LG port commandos or Indy 360-2's on a 408 would easily kill those 500hp numbers.
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Post by Jeff »

Check out Hughes engines.com, all they do is mopar. I just ordered up most of the parts for a 408 stroker, and they are very helpfull with tech questions. They also have a lot of info on there site. Its worth a look.
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Post by devilbrad »

One thing to be aware of with the roller blocks, both early and Magnum. The lifter bores are a good 1/4" taller then standard LA blocks. Its very hard to find solid roller lifters that will actually work without haveing to spot face top of lifter bores. There are actually plenty of hydraulic roller grinds, just check the 92 and up Magnum engine listings, those cams will work, but the factory lifters dont like to rev without giving up past 5500rpm. Crane makes a killer solid roller lifter that oils through pushrods part number 69550-16. You will need to bush lifter bores though. Also, the Jesel solid roller Viper lifters are said to drop right in using the exsisting lifter retention setup, but at 2k for a set of 20 I dont know anyone who wants to try! Last but not least, you can convert the hydraulics to solids by gutting them and building a spacer, just make sure it will still oil through pushrod. About the only difference between the roller block and the Mag block is this......Mag block has extra motor mount bosses for bolting into the trucks and it DOESNT have the oil passage to oil through heads, so you are stuck with Mag style heads, or external oiling. I'd use the Mag block with the Eddy Mag heads, a custom ground solid roller, the afformentioned Crane lifters, and do the 408.
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Post by ou812 »

Nothing special with my combo...but I wouldn't really recommend stock components to my customers...I just threw this together to get any bugs worked out from building the car.
It's just been a very reliable and powerful build. I used arp rod bolts, internally balanced the crank, did a SS type hone on the rods, KB hyper pistons, and did a few things that no one else does to the oil pump and suction side of the oil system. Pressure side is all stock sizes!
When I build any sb up for racing, I use Manley I beam rods, scat cranks and either manley, ross or JE pistons.
Ryan only does SB mopars, but he's not the only sb mopar guy with experience...there are plenty others out there.
Brian
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