Low deck hemi

13714 Views 24 Replies 9 Participants Last post by One job johnny, 8 mo ago

HemiBLow

Discussion Starter · Mar 18, 2014

Anyone done a low deck hemi?

I have a set of Stage V conversion heads and am planning a 500ci low deck motor for my 69 GT. I know I will have to build an intake, but was going to do that anyway as it will be EFI and boosted.

Can you think of any reason I couldn't use the heads on a low deck?

Thanks!

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chryco

· #2 · Mar 18, 2014 (Edited)

The low decks were pioneered in the early 80`s for prostock and comp dragster applications. At the time hemi blocks were drying up and heads were going for a premium (enter stg.5 conversion heads) . The blocks had the extra bosses furnace welded in so original gen II heads would fit . The prostock effort didn`t get that far unfortunately (see Charlie Maluke) But Dave Koffel and Wally Dyck held the A/Dragster records for years. The engine was / kind of high dollar to build and became obsolete when better big block heads came out (Zeeker / B1 / Indy ) .
Neat project motor , but will be a little $$$ because of all the custom stuff to be fabbed and then made to work, the kind of motor they would build for Engine Masters . If you`ve got access to a dyno for testing parts ....great. You do know the stg 5 heads are a bit of a compromise to fit the B/RB platform , right? In the end a set of Indy`s or your choice of big block heads might be less headaches .
A low block hemi will scream and make big power , but with today`s wedge heads will probably pale in comparison .
My $0.02
chryco

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roccodart446

· #3 · Mar 18, 2014

how well does a stage V conversion perform? Compared to a ported set of good heads 3200$ or more. I've always wondered how well these would work and if it would be worth it.

bOb shingler

· #4 · Mar 18, 2014

just build it

I'd like to follow the build tread.

HemiBLow

Discussion Starter · #5 · Mar 19, 2014

Well we all gotta make choices.

The bad - I have limited funds and limited time left to get something done.

The good - I have two mopars. A 69 Dart Gt that was my grandfathers and I took my drivers test on and a 68 GTX I drove in high school. I've got a bunch of parts.

The choices - I love big blocks, I love boost, I don't like holes in the hood and stuff in front of my face when I drive. Which motor in which car. Blower or turbo.

I'm doing the GTX now. I have virtually all the stuff. Stroked 440, all iron. Turbos in the front, doug nash race 5-speed, keeping the 8.75 till it breaks. Putting quarters on, doing mini-tub. Plan to be driving by end of summer.

The Dart... The lure of the big motor in the small car. Bought the Stage V heads years ago from a guy getting divorced. Brand new, beautiful, and cheap. Love the guys ex-wife! Just seems like with a low deck block the hemi would fit better in the dart. The pistons are the worst of the custom parts. I planned to fab an intake anyway. I'm not worried about the oiling and pushrods. Have a 4l85 and a dana60. Car has air and it's staying. A screw blower like I have on my Mustang would be great but one big enough is about 10K. Probably turbos but I don't know where they would go yet, not likely in the front.

Ultimate power? No. Plenty for street cars? I think so. And I drive them.

Fulfilling a dream since high school. Priceless.

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HemiBLow

Discussion Starter · #6 · Mar 19, 2014

Do I have to tell you what my wife thinks of my car hobby?

Thank god I have a son who will stop her from having the worlds biggest garage sale! Even if he did rip the front end off of my Mustang I loaned him on prom night!

HemiBLow

Discussion Starter · #7 · Mar 19, 2014

69 Dart. The before pic.

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bOb shingler

· #8 · Mar 19, 2014

i don't think you'll get much heat up thru the hood and what is a nickle pellet?

HemiBLow

Discussion Starter · #9 · Mar 19, 2014

bOb shingler said:
i don't think you'll get much heat up thru the hood and what is a nickle pellet?

The car hasn't moved from this spot in 30 years. My grandfather was a bit of a hoarder.

My father was a chemist and worked on auto catalytic converters. He got the barrels from work. He stored hub caps in them.

The Dart will be moving very soon.

chryco

· #10 · Mar 19, 2014

Go with your dreams Bro ! I did !
chryco

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HemiBLow

Discussion Starter · #11 · Mar 20, 2014

Now that's what I call a dream!

HemiBLow

Discussion Starter · #12 · Mar 20, 2014

And give up that numbers-matching all-original 273?

chryco

· #13 · Mar 20, 2014

HemiBLow said:
And give up that numbers-matching all-original 273?

You could always twin turbo the 273 !!?? LOL ! Here`s a former member`s old car !

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HemiBLow

Discussion Starter · #14 · Mar 21, 2014

I know, a stroker small block would fit a lot better and still make good power. The hemi would fit better in the GTX.

In high school, before I got the GTX, I drove a 68 Coronet, 318 auto. Put on headers, 4bbl, etc. I thought it was great. Then I got the GTX, 440, 4 speed. Holy shit! Most of my money went to gas, tires, and tickets! I've just never have really been that fond of small blocks since.

I thought about doing a stroker 5.7 hemi. I have an 03 Ram 1500 hemi. It runs decent, but it ain't no big block! Boosted would probably be pretty good.

It's going to be a street car, I don't need a hemi.

But what I really WANT is the real hemi in the dart.

I even already have most of the parts. Just got to make the time.

There are so many beautiful cars and great builds on this site. It can be done.
I look around here for a while and I can't wait to get back in the garage!

I just need to learn the F-word. FFFFF... Finish!

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Helmine

· #15 · Mar 25, 2014

just before NHRA switched to 500 cu in with no weight breaks, the low deck hemi actually held the PS speed record. I thought Hemi would have become a major factor with 500 cu in, but didn't happen. I really don't understand the point here much. In the original build ups fitting the 2 gen hemi heads tot eh B-block, the pushrods actuaaly went in to the water jackets and there had to be done some welding too. Perhaps the conversion heads are a little better in that sence, but still that situation is worse with the lower block. The RB requires clearancing too with hte conversion heads. However, the biggest problem I see with a boosted low deck hemi is, that why on earth would anyone want to build such an engine on a block that can barely stand around 800 hp in the long run? You can run in to problems with a naturally aspirated wedge!

HemiBLow

Discussion Starter · #16 · Mar 27, 2014

Helmine said:
just before NHRA switched to 500 cu in with no weight breaks, the low deck hemi actually held the PS speed record. I thought Hemi would have become a major factor with 500 cu in, but didn't happen. I really don't understand the point here much. In the original build ups fitting the 2 gen hemi heads tot eh B-block, the pushrods actuaaly went in to the water jackets and there had to be done some welding too. Perhaps the conversion heads are a little better in that sence, but still that situation is worse with the lower block. The RB requires clearancing too with hte conversion heads. However, the biggest problem I see with a boosted low deck hemi is, that why on earth would anyone want to build such an engine on a block that can barely stand around 800 hp in the long run? You can run in to problems with a naturally aspirated wedge!

Wow!

To be honest I really hadn't figured the pushrod clearance to be that much of a problem. The clearancing required on the RB for the Stage V conversion heads is not very much. I already did it on a 440 block. I have a spare B block, I guess I better stick the heads on and find out before I go any further.

As far as blocks go, Indy makes a fine aluminum B block that would have no problem handling the power. While it seems kind of pricy, if you consider that no main girdle, studs, main caps, or machine work would be required, it becomes more reasonable. I also REALLY like the idea of an all-aluminum hemi for the Dart! The Indy block is only about a hundred $ more than a friend of mine just spent on an aluminum RHS LSX block and it looks just as beautiful.

I have most of the parts already, $5k for the block and pistons doesn't seem all that bad.

Thanks for the headspin! That is exactly what I am looking for!

HemiBLow

Discussion Starter · #17 · Mar 29, 2014

5

Ok, I dug out my B block and put the stage V head on to see what the pushrod clearance looked like. It's really not any different than it was on the RB block.

The marks on the block would cover the entire pushrod hole in the head. It would certainly not need to be clearanced that much just to adequately clear the pushrod. It looks like the pushrods will be riding high in the hole as well.

I'm going to have to make up some pushrods the correct length before I actually grind it but I don't see any problem.

Has anyone used the BRC main girdle system? It looks like it would give a lot more strength to the stock block.

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Dodgeguy101

· #18 · Sep 18, 2014

HemiBLow said:
Ok, I dug out my B block and put the stage V head on to see what the pushrod clearance looked like. It's really not any different than it was on the RB block.

The marks on the block would cover the entire pushrod hole in the head. It would certainly not need to be clearanced that much just to adequately clear the pushrod. It looks like the pushrods will be riding high in the hole as well.

I'm going to have to make up some pushrods the correct length before I actually grind it but I don't see any problem.

Has anyone used the BRC main girdle system? It looks like it would give a lot more strength to the stock block.

How is this coming along? Do what you want to build the engine. Took me 30 years and a divorce to finally get my Demon running. Just do it. I too would love a hemi, maybe in time, but just do it, dreams are there to made into reality.

Where in MD are you?

mzak88

· #19 · Oct 9, 2014

HemiBLow said:
Ok, I dug out my B block and put the stage V head on to see what the pushrod clearance looked like. It's really not any different than it was on the RB block.

The marks on the block would cover the entire pushrod hole in the head. It would certainly not need to be clearanced that much just to adequately clear the pushrod. It looks like the pushrods will be riding high in the hole as well.

I'm going to have to make up some pushrods the correct length before I actually grind it but I don't see any problem.

Has anyone used the BRC main girdle system? It looks like it would give a lot more strength to the stock block.

wanna sell those stage v's? ive been trying to buy from them since may :banghead

440outlawdart

· #20 · Oct 11, 2014

heres a pic on how it was done with a b block in pro stock years ago

Photograph Font Engineering Machine Audio equipment

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