Hemi Vs Hemi....??? kinda long.......

[Lee Pritchard]

426 hemi Vs stroker hemis.....

I have install a few 528 crate hemis as well as a ray barton 528 hemi and a few 472 custom built hemis and none of them have run like i would think they should have.


First case.....

67 gtx, ray barton 528 , 11.2.1 compession 575 lift soild cam , two fours,410 gear, 3800 convertor weight 3900....ET 12.20

67 gtx sox and martin clone, 426 cid 30 over 12.5.1 roller cam 700 plus lift, cross ram, 410 , 4200 convertor weight 3700 ..ET
9.80

Second case..

70 super bee .. Hot Rod magazine Hemi Rumble Bee.. dick landy built 528 (750 hp) ET 10.60

68 super bee..home built 426 hemi , 30 over ,small roller cam, 12.5.1 compression, 410 gear, 69J convertor .. weight 3900 pounds.. ET 10.38

68 super bee (same car as above) we pulled the 426 and added a 472 hemi , indy heads, 13.5.1 compression, 750 lift roller cam. 456 gears , 69 j convertor, indy cross ram and two 750 holleys..ET 10.42...

It seems to me that the 426 that Tom Hoover came up with in a few short weeks was the best design.. Just look at super stock A cars high 8s with stock bore and strokes .. I go to a lot of races and the faster hemis are not stroker engines...Now i'm talking carb motors NOT blown motors

Bottom line......stroke a wedge?? by all means it makes a ton of power over a standard RB motor......Stroke a hemi?? What do you think??? Sure the 426 hemi i have listed do have more lift and compession ratios and one has less weight but that doesn't make up for the wide range on the ETs from 9.80 to 10.60s.. Even 300 pounds difference would only make up for 3 tenths at best.. One would think the cubic inch difference would make up that lost 3 tenths ( 426 -528) =102 cid.....What do you guys think???.......................Lee...........

[Doug Wilson]

I THINK... I wish I had your experience with Hemis. I have no idea what they oughtta do, but I think you are right. It makes sense that the Hemi "magic" would be more noticable naturally aspirated than blown, although they still have some advantage.
Best I can do... sorry.

[KM]

I do agree and do not.

Your examples only shows that those strokers were not making what they should have been....or those 426´s were made really good !

I could throw you as many examples as you wish where I show you that wedge should NEVER be stroked.

One 440 built to produce 772hp and one 493 built to produce 511 hp..........

Hemi heads flow air.....massivly.....stroked or not !

Hemi will respond to stroking......when built right.

Kimm

[mr_340]

I've always thought that the heads limit the HP produced. The larger engine will make about the same HP as the smaller engine, just at a lower rpm. This would assume that other factors would be optimized for maximum power for that engine.

In your first case, the gear ratio stayed the same. Perhaps the gear ratio favored the 426 more than the 528. Do you have any dyno data on these two engines? It would be interesting to compare the power and torque curves of each engine.

[Marc]

To attribute a car's poor performance to the stroke of the crank is ludicrous.
It's assuming every possible factor for performance lies with the Hemi's extra stroke.

Tuning?
Chassis?
Etc?

LOTS of things have obviously been overloooked if an 11.2 compression 528 Barton Hemi is running 12.20's.

[Lee Pritchard]

Mr _340 the only dyno numbers i have are what dick landy said the 528 motor in the hemi rumble bee (750 hp) My 499 wedge made 749 hp on the dyno and at 3600 pounds it ran 9.72@139.79...... The 528 hemi super bee only ran 10.60.. These numbers are Dick Landy and Hot Rod magazines, NOT mine....The ray burton motor was said to make 650 hp easy.. The stock 426 hemi that the 528 replaced ran 12.90s... we tried 456 and 410 gears in the car, 410 worked best with the 528 while the 456 worked best with the 426...We have a 354 in the car now but have not tried it at the track yet... We also tried 3 convertors from 2200 to 3800.. the 3800 being the best of the 3... we tried changing the cam timing , 106 was the best setting and thats what the cam card said.. carbs where sent to two different places with no help.... we even tried a single four (holley 950 hp) it was a known good carb , it came of my 70 roadrunner that runs 11.20s. Compession tests and leak downs showed good... I have no answer to the why it doesn't run better...but i can tell you this it doesn't have 650 hp....I have the first motor that was in the 68 super bee (426 cid) and i'm going to put it in my 70 roadrunner in place of my 499 wedge and see how it runs...also my friend just installed a m/p 528 in his roadrunner and i got a chance to drive it today... While it runs great it wouldn't out run my wedge.....Lee....

[Lee Pritchard]

Marc i'm not assuming anything...I'm just telling you what i have seen....and asking what you have seen.... after having many stroked wedges i would never build a 440 again and i would like to say the same of a stroked hemi.... but all i have seen is stock stroke 426 hemis running better that the strokers.....if you know of some stroked hemis that run better please ring in ....give us some info on them...I love hemis and would love to have a 528 or bigger(572) that would run like a raped ape.. I'm going to toss in one more case......Dave Duell runs a 65 wagon with a 572 wedge and to my best info (his carb man) it has run 9.30s . He had a 572 indy hemi built and has not run as good...This hemi made over 1000 hp on Hot Rod TV ... His old wedge motor made 900 hp... His carb man said he was not altogether happy with the hemi and was thinking of putting the wedge back in.... thats second hand info so dont take it as the full story.......Lee.....

[Marc]

My Barton stroked Hemi should be here in 6-8 weeks, I'll post what the slug runs when I take it to the track....


I think if an engine DYNO's at 900hp and won't run strong it isn't neccessarily the fault of the ENGINE.
Just as an engine needs to be built as a PACKAGE, so too does the entire CAR.
Something/somebody is not setting up those cars right, IMO.

[Lee Pritchard]

Cool Marc let us know when you get to make some passes!!! It seems most people run wedges these days , So it's good to see some hemis posts.....I got turned on to mopars as a kid because of the king kong of motors the hemi!! Maybe not all hemis run good but at lease they scare the hell out of the ford and chevy guys when they look under the hood .. ....Lee....

[KM]

Comparasion:

First case.....

67 gtx, ray barton 528 , 11.2.1 compession 575 lift soild cam , two fours,410 gear, 3800 convertor weight 3900....ET 12.20

My 69 Charger,Ray Barton 471, 10.5:1 comp, 580/560 lift solid cam, one four,410 gear, 4000 convertor, weight 4200.....ET 11.5
There really is something wrong in that GTX.......my Charger is a (real) street machine.......

By the way, with a (too) mild 493 wedge it´s ET was 12.5 !

Kimm

[DartGT66]

Since an engines ability to make power is pretty much based on how much air / fuel can be get in to it and burned effectively in a certain amount of time, I just can't see why adding displacement would result in less hp. But I don't seem to understand a lot of other things either.

[Marc]

LOL
I'm the same way.
Women have me puzzled, for instance................

[DartGT66]

Yeah, they sure give the word "logic" a whole new meaning....which is nice......kind of......occasionally.

[Maxwedge]

Dart....HAHAHAHAH "occasionally"..so women are the same in Finland? HHAHAHHAHAHA
Where is Jamze?

[Lee Pritchard]

KM funny thing is that 528 in the gtx feels real real strong...in fact it feels faster than my wedge, but the ETs dont are not even close.....MY home built wedge is real mild also ....4.375 bore , 4.150 stroke isky 292 505 hyd cam , ross flat tops,stock rods, edelbrock heads, edelbrock rpm intake,950 hp holley.... stock convertor, 355 gears, hooker small tube headers , all steel 70 roadrunner with power brakes and power steering..I have never weighed it but i would guess 3600 to 3700 pounds....... best ET to date in the heat and a greasy track was 11.21 @121... This is my daily driver and it gets better gas milage than my 98 360 ram truck.....Lee....

[djswwg]

This all very interesting to me, and since I don't have a bunch of hemi's around to play with, I can only conclude the following. Assuming correct combinations on each car and proper fine tuning on each engine, the problem likely lies in valve sizes and or rod ratios. Both affect cylinder head head flow, rod angle and piston speed, and these are the most crucial factors that determine an engines power characteristics. Just my opinion, based on what I know, and of course, what I don't know!...........djs

[wedgehead]

I agree with most of the posts that I've read. When you stroke an engine you had better know exactly what parameters that you're actually changing. Rod ratios,piston speed and dwell, etc. When these parameters are changed rhen your cam specs will also change for this particular setup. The Hemi needs a bunch of compression I would think to really work. I remember when the Hemi first came about there was a 12.5 to 1 version and there was a 13.5 to 1 version. These were factory engines, so if you are building a HP version I would think that you'd need at least that same amount of compression. This is only one aspect of this motor. Also the Hemi like to rev!!! Wedgehead

[KM]

Lee,
I really think that yours stroker wedge is impressive.
Those are great numbers for such a mild engine.
I do feel that that Hemi does not work like it should.
I would check it out if it was mine......

Wedgehead,
Somewhat have to disagree.
Hemi does like comp but IMO so does wedge.
Hemi´s comp does not HAVE to be pumped up to produce hp.....

Max,
I strongly believe that women are not so much different in so cal or Samoan Islands or Japan than they are in Finland.....
Oh well, guess we have to bare them anyway

Kimm

[DartGT66]

The lack of CR was Landys explanation why the bee didn't run better than it did. Remember the old BB shootout in Hot Rod, where the wedge Bee that made 736 hp run high 9's? NTW, was just checking some blueprint specs from the NHRA site; the 10.25:1 Hemis CR in Stock is around 11.7:1 and the '68 race Hemis in SS 14.4:1.

[wedgehead]

KM: I don't totally agree that a wedge likes or needs compression as much as the Hemi. It's according to which wedge you're speaking of. The 440 was built with torque in mind. Now, the 340 was another story. 5500 rpm max for 440, 7000-7500 for the 340. Just one example. The 440 in many instances would make gobs of torque but hp numbers were considerably lower compared to the amount of torque produced. On the other hand, the 340 would produce less torque compared to the gobs of hp produced from the "Little Big Block". IMO, I think the Hemi thrives on compression because of the huge amounts of air & gas that it's able to burn and also the efficiency of the combo. The Hemi design is almost perfect and this explains why it is still the baddest motor that has ever been made!!! Wedgehead

[KM]

OK,
I did speak 440 vs Hemi.
You might very well be right about that Hemi gains more when cr is pumped up,,,,,,,still I have seen and read about "low" cr Hemis making nice numbers meaning that it does not HAVE to have high comp. to produce good hp.

Kimmo

[Maxwedge]

when you stroke and or increase the bore size you also decrease the amount of dome required to hit those high CR. Advantage Stroker motor. You then have lightened the pistons and reduce the stress from that side fo the equation. the down side is the rod now has a tougher time pushing the piston up the bore. The ShotGun Hemi ford rules many classes of IHRA, with its 800ci limit for a reason. I have a feeling that something more than the big cubes is causing the cars to be slow.
JMHO
MW

[Doug Wilson]

I recall reading an SAE paper some time ago, which analyzed the effects of increasing compression ratio. It made the statement that at (about) 11:1 you reach of diminishing returns, where further increases don't provide the equivalent amount of power gains as increases up to 11:1 do. In other words, if you gain, say 4 percent per point up to 11:1, after that point the increase in power might be perhaps 1 percent. These figures are inexact because of my memory, but you get the idea.

[MitchB]

Very interesting reading this. I come from a different angle. I have owned a Boss 429 Mustang since 1977. This was Ford's hemi. The Boss really responds to increased displacement. In Fact, you almost have to add displacement because the heads are so big. I can't say why the Chrysler Hemi would not respond similarly. I for one would like to know.

Mitch

[Lee Pritchard]

Mitch i also had a boss 9 back in the late 70s....One hell of a motor with the right parts .... mine had a 660 lift cam , big tube headers, 1050 holley, 488 gears, top loader .... and you are right about the port size, you could take a 16 oz RC cola bottle and stick it right in the port!!!.....A hemi port is smaller for sure..... the only problem with a shot gun hemi was the S turn that the fuel had to make in the chamber from the intake to exhaust ..mikey tomson did have a funny car that run very well and bob glidden was kickin ass with his hemi in prostock....I wish ford would have had a few more years to work the bugs out, We might have seen more than one hemi in top fuel and funny car if they did.....Lee..

[Lee Pritchard]

I wanted to add this... i had a chance to talk to a old pro stock racer a few months back before his death... He was 78 and had some miles on him but was still building motors for super comp racers....While bench racing late one nite the hemi came up, he said he could make more hp with 426 inches than a 472 or 500 inch motor... when ask why he said rod angle , dwell time,and piston speed ect .... He said the stock 1.8 rod ratio was the best ...So i asked what if i keep everything the same ratio and came up with 500 inches.....he said the heads would also need to flow more to match the extra cid..... Then we changed to 340 motors...... I wish now i would have picked his brain a little more on the hemi........ oh well i missed the boat on that one ....Lee..

[DartGT66]

Sounds strange to me. The Hemi has got a slightly "better" rod ratio than the wedge in stock form, and in the stroked form too. The Hemi heads outflow wedge heads easy. There are even some other brand engines that have rediculous rod lengths, still I have seen a quite a few of them run decently. I am not familiar with hemis, but what I have seen at the tracks the wedge seems to be way less sensitive to anything than a hemi to run well.

[MitchB]

I wanted to add this... i had a chance to talk to a old pro stock racer a few months back before his death... He was 78 and had some miles on him but was still building motors for super comp racers....While bench racing late one nite the hemi came up, he said he could make more hp with 426 inches than a 472 or 500 inch motor... when ask why he said rod angle , dwell time,and piston speed ect .... He said the stock 1.8 rod ratio was the best ...So i asked what if i keep everything the same ratio and came up with 500 inches.....he said the heads would also need to flow more to match the extra cid..... Then we changed to 340 motors...... I wish now i would have picked his brain a little more on the hemi........ oh well i missed the boat on that one ....Lee..

You might be on to something. Most engines need the increased piston dwell at TDC to give the heads more time to fill the chamber. But remember the Hemi has no quench area and probably has a slow burn rate, relatively speaking. This is exacerbated by using high compression domed pistons. So in this case, it would benifit as much if not more by allowing the piston to dwell at TDC during the power stroke where more time would be given for a slower flame front to propogate through the chamber. Here, you would be able to time peak cylinder pressure more closely with maximum mechanical advantage.

Re the Boss: towards the end of it's reign in Nascar, Ford did 'D' the intake port by raising the port's floor. This supposedly was good for about 30 HP on what was a 625 HP engine. Oddly, the full Hemi heads without the quench pads made less power. The trend in later years was to greatly increase the quench area, making the chambers very small. These heads made the most power. So in the case of the Boss, the trend was to reduce intake port area while increasing quench area.

To see more on the heads Billy Glidden used in Pro Stock, go here: http://www.theoldone.com/boss429head/index.html

Mitch

[Tarrbabe]

I know squat about the Hemi, but this makes good reading. I remember an article with Richard Petty years ago and he said they ran rod angles of around 1.9 when they were running their best. They built some 2.0+ motors and said they wouldn't run so they went back. The factory reps. were the ones that told him to try the longer rods. Don't know how much this relates to street or drag, but you have to admit, they make those motors run and stay together. Sorry, just thinking out loud.

[Craig]

Lee, this is very interesting and I have a little experience to add. There are so many variables in the cars/ chassis that it is hard to compare. But I think that Hemis SHOULD respond better to stroking than wedges.

I have a 67 Dart with a Hemi. I got it in 1982 but was not able to race it until 1998. I ran it with the parts that it was built with in 82, stock 3.75 crank, 12.5 TRW pistons, .785 roller, unported magnesium crossram. It had 5.38s in the Dana because it was a 1/8 mile car, but since I changed to a low-slip Dynamic converter I figured it would do for the 1/4. The best I was able to get was 10.3s at 129 mph, turning 7500 trap rpm on 14x32s.

Then I had the heads freshened at Ray Barton's, mainly for peace of mind and not wanting to drop a valve, and decided to get a good porting while they were there, since that's his specialty. He said porting wouldn't help with the stock crossram which only flows 350 cfm per port, but I wanted it out of the way since I figured I would change to a better flowing intake myself later. After porting they flowed 441 cfm. Car ran the same, but at least I trusted the valves to stay put.

I was disappointed that I couldn't do better than 10.3/129. And I was getting worried about the quality of the bottom end build, hitting 7500 rpm in the traps, and Barton convinced me that those old pistons didn't seal well at power. So I gave him the engine to be re-done. The way I was running it he dyno'd it at 650 HP at 6500, 557 ft-lbs at 4900. On tear down he found the actual CR was around 11:1 due to the undecked block.

He put in .030 13:1 JE pistons, a new .737 roller, and the usual blueprinting. I decided I wanted a 4.15 crank too and Ray thought that would be beneficial. But he predicted nothing would get it above 730 HP with the stock crossram. The 477 dyno'd 770 HP at 6600, 669 ft-lbs at 5100. He thought the 4.15 crank must have made the difference, because at that time it was the first time he had used one with a stock crossram. I got some 4.56 gears to bring down the trap rpm but wanted to baseline the car with the 5.38s first.

Back to the track and found the real reason the car had been only going 10.3s with 650HP in 3420 lbs. The pinion bearings in the Dana were gone and the gears were binding up under power, though they turned freely by hand. The rear had been improperly assembled by the previous owners around 1980! Rebuilt the Dana with 4.56s and ran 9.9s at 136, but got kicked off the track after a few runs for no cage cert. I hope to get back out this season with the new cage and sort it out. 770HP in 3420 lbs should be quicker/faster than 9.9/136.

Hard to say what helped the most when I changed so many things at once, and never had a good rear behind the 426. But my thinking was that with the great head flow of a Hemi, that it would like the stronger vacuum pulses of a stroker. The SS motors are making 900HP with stock stroke and around 420cfm ports with good manifolds. That stock crossram is like a restrictor plate on mine, but it looks cool and nostalgic. With a decent manifold, mine should be similar to a SS motor with a 4.15 crank added (minus the crazy detailed blueprinting the SS motors get). So I'm hoping to find the opposite of your experience, that a ported Hemi likes a stroker crank. If not, I've still got the 3.75 Kellogg crank!