Repco head.

General engine tech -- Drag Racing to Circle Track

Moderator: Team

Circlotron
Expert
Expert
Posts: 793
Joined: Tue Feb 05, 2013 6:56 am
Location: Melbourne, Australia

Re: Repco head.

Post by Circlotron » Sun Dec 02, 2018 7:17 am

The things that gets me with the Repco head is they had a golden opportunity to have individual inlet ports instead of three siamesed ports!!! Why oh why did they make totally the wrong decision??? The Valiant Hemi 215, 245 & 265 all had individual ports.
Image

User avatar
Stan Weiss
Guru
Guru
Posts: 3709
Joined: Tue Feb 20, 2007 1:31 pm
Location: Philadelphia, PA

Re: Repco head.

Post by Stan Weiss » Sun Dec 02, 2018 10:25 am

Circlotron wrote:
Sun Dec 02, 2018 7:17 am
The things that gets me with the Repco head is they had a golden opportunity to have individual inlet ports instead of three siamesed ports!!! Why oh why did they make totally the wrong decision??? The Valiant Hemi 215, 245 & 265 all had individual ports.
Image
Why would someone make a head like pictured and not make it a cross flow?

Stan
Stan Weiss / World Wide Enterprises
Offering Performance Software Since 1987
Do you use engine simulation software that uses cylinder head flow files?
We have a package of more than 3000 DFW or FLW Files

cjperformance
Guru
Guru
Posts: 3218
Joined: Tue Aug 19, 2008 7:20 am
Location: South Australia

Re: Repco head.

Post by cjperformance » Sun Dec 02, 2018 3:23 pm

Stan Weiss wrote:
Sun Dec 02, 2018 10:25 am
Circlotron wrote:
Sun Dec 02, 2018 7:17 am
The things that gets me with the Repco head is they had a golden opportunity to have individual inlet ports instead of three siamesed ports!!! Why oh why did they make totally the wrong decision??? The Valiant Hemi 215, 245 & 265 all had individual ports.
Image
Why would someone make a head like pictured and not make it a cross flow?

Stan
The pictured head is an aftermarket head designed as a direct fit improvement on factory.
But initial design, because Chrysler Australia engineers copied the open chamber Cleveland head but needed to not make that so obvious! :lol:
Craig.

numboltz
Member
Member
Posts: 147
Joined: Tue Feb 28, 2012 3:54 pm

Re: Repco head.

Post by numboltz » Sun Dec 02, 2018 8:51 pm

"...Interestingly , the Rolls Royce Merlin Mk 1 engine used the same ramp head as they called the design used by Repco ,it did not go past development ,the mk2 that did go into production had parallel vertical valves [both were four valve]."

IIRC, the R-R ramp-head design was dropped because of casting issues, although the replacement design
did look like a better bet for HP, although I have always speculated that the 1710 combustion
chamber was even better, as far as avoiding detonation with a given fuel quality. But, they made
the fuel quality needed back in the day.

Geoff2
Expert
Expert
Posts: 996
Joined: Mon Nov 09, 2015 4:36 pm
Location: Australia

Re: Repco head.

Post by Geoff2 » Mon Dec 03, 2018 4:12 am

CJ,
Chrysler didn't copy anything from Ford. C already had the poly head & the Hemi, dating back to the early 1950s, for ideas. Further, design of the inline Aussie 'Hemi' started in early 1966, loooong before there was a twinkle in anybody's eye at Ford about the Cleveland design.

As far as state of 'tune' of the Repco head v C, look at the #s, very close. Peak power & tq for the Repco 5500, 4000 rpm; E49 Hemi 5600,4100. Not some 7000 rpm screamer. The E49 was a success because Chrysler got it right, as Chrysler does.

cjperformance
Guru
Guru
Posts: 3218
Joined: Tue Aug 19, 2008 7:20 am
Location: South Australia

Re: Repco head.

Post by cjperformance » Mon Dec 03, 2018 4:50 am

Geoff2 wrote:
Mon Dec 03, 2018 4:12 am
CJ,
Chrysler didn't copy anything from Ford. C already had the poly head & the Hemi, dating back to the early 1950s, for ideas. Further, design of the inline Aussie 'Hemi' started in early 1966, loooong before there was a twinkle in anybody's eye at Ford about the Cleveland design.

As far as state of 'tune' of the Repco head v C, look at the #s, very close. Peak power & tq for the Repco 5500, 4000 rpm; E49 Hemi 5600,4100. Not some 7000 rpm screamer. The E49 was a success because Chrysler got it right, as Chrysler does.
:-) my father and uncle both started at chrysler here in lonsdale in 1966 and 1967 respectively. So i have great respect for our local product. I can tell you there was a LOT of spying, buying, comparing between the big 3 here at that time. Nothing to be ashamed of, they all did it! But, every time i see a hemi head i cant help rev up the Chrysler boys as they are a very patriotic and sensetive bunch, once they convince me its no Clevo copy , lol! I follow with , ah !! Its obvious that its a ford 240/300ci 6cyl copy! Gets a bite every time, just good fun.
And on that note, the E49 was a sucsess because C.A.L. could not get it right and knew it!, and that is why they got the Italians to finish sorting it for them!, and yes they did a fine job.
And , why do all the chrysler boys say the E49 was faster than the GTHO? But when they try to prove that they show the 1/4 mile times for the GT not the GTHO?! :roll:
Craig.

grandsport51
Pro
Pro
Posts: 261
Joined: Sun Jan 14, 2007 11:47 am

Re: Repco head.

Post by grandsport51 » Mon Dec 03, 2018 6:44 am

Interesting link to the designed in USA 6cyl Valiant Hemi!
https://www.valiant.org/valiant/hemi-six.html
Dave B.
LIGHT 'EM UP

pdq67
Guru
Guru
Posts: 8165
Joined: Thu Mar 04, 2010 8:05 pm

Re: Repco head.

Post by pdq67 » Mon Dec 03, 2018 3:45 pm

I guess that I don't understand why Chrysler Aust. didn't install real 1950's MOPAR V-8 designed, (but made for 6 banger's), Hemi heads on their straight 6 cylinder engines.

They would have had cross flow and a true Hemi shaped chamber.

Pleas tell more here, I want to learn!

pdq67

PackardV8
Guru
Guru
Posts: 5542
Joined: Sun Jul 30, 2006 2:03 pm

Re: Repco head.

Post by PackardV8 » Mon Dec 03, 2018 4:41 pm

You mean like this one?

Image
Jack Vines
Studebaker-Packard V8 Limited
Obsolete Engineering

grandsport51
Pro
Pro
Posts: 261
Joined: Sun Jan 14, 2007 11:47 am

Re: Repco head.

Post by grandsport51 » Mon Dec 03, 2018 5:43 pm

For A bodies only says the hemi slant six is a photoshop job?
The Hemi slant is an elaborate hoax. It was claimed to have welded two late model Hemi heads together...blah blah blah. But those pics and a few fake "under construction" pics are all that exist. The EFI slant however, has been around a long time. Just go to rancefi.com and see. Rance is da man.
So the hyper pac was the ultimate factory Slant Six

https://www.allpar.com/mopar/hyper-pak.html
Dave B.
7A74952B-D1F5-4957-84C0-318052C26CB0.jpeg
You do not have the required permissions to view the files attached to this post.
LIGHT 'EM UP

pdq67
Guru
Guru
Posts: 8165
Joined: Thu Mar 04, 2010 8:05 pm

Re: Repco head.

Post by pdq67 » Mon Dec 03, 2018 7:57 pm

PackardV8 wrote:
Mon Dec 03, 2018 4:41 pm
You mean like this one?

Image
Jack,

Is this for real??

If so, do you have any tech info. on it?

pdq67

grandsport51
Pro
Pro
Posts: 261
Joined: Sun Jan 14, 2007 11:47 am

Re: Repco head.

Post by grandsport51 » Mon Dec 03, 2018 8:55 pm

The split Headers for the front 3 cylinders on that phantom Chinese Six "Hemi" look like Harry Millers exhaust design for the '35 Indy Fords with zero clearance (scuttled the Fords chances with steering gears seizing) doubtful that Mopar steering gear could work for more than a day before it was destroyed by the heat !

Dave B.
LIGHT 'EM UP

gruntguru
Pro
Pro
Posts: 205
Joined: Fri Apr 10, 2015 7:56 pm

Re: Repco head.

Post by gruntguru » Tue Dec 04, 2018 12:41 am

pdq67 wrote:
Mon Dec 03, 2018 3:45 pm
I guess that I don't understand why Chrysler Aust. didn't install real 1950's MOPAR V-8 designed, (but made for 6 banger's), Hemi heads on their straight 6 cylinder engines.
Money.
The Hemi 6 uses a pedestal system. Valve stems canted but all in one plane.

Geoff2
Expert
Expert
Posts: 996
Joined: Mon Nov 09, 2015 4:36 pm
Location: Australia

Re: Repco head.

Post by Geoff2 » Tue Dec 04, 2018 5:14 am

CJ,
From Top Aussie Supercars testing, tested all the Aussie muscle cars of the era.

Fastest: E49 Charger, 14.4 secs. With these comments: " You can drive around town at a steady 1500 rpm-30mph- & never feel the need to change down unless you want hard acceleration." Fuel consumption overall 13.8 mpg, cruising 15-17 mph.

Phase III GTHO Falcon. 14.7 sces. With these comments: " ...it will crawl along from 1500 rpm in top...[but] doesn't entirely hide it's displeasure..". And: " This sort of of low speed flexibility was NON_EXISTENT in the old car. It bucked & shook at 40 or below."
Fuel consumption: Hard pushed 8mpg, 'quieter' driving 10.4 mpg. Gotta love them Holleys...

Charger 340 also beat the GT Falcon, 0.8 sec quicker to 100 mph. GT supposedly had 25 more hp. Hmm...

cjperformance
Guru
Guru
Posts: 3218
Joined: Tue Aug 19, 2008 7:20 am
Location: South Australia

Re: Repco head.

Post by cjperformance » Tue Dec 04, 2018 5:32 am

Heck ,, the GTHO is getting even slower as the years roll on! :lol:
Craig.

Post Reply