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  #1  
Old 01-05-2002, 04:00 AM
440DARTGT 440DARTGT is offline
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Default 451 vs 470

Alright, I know this has been spoken about before but before i go
get spending on $$parts next month, I need to know the true HP and benifits of the 470 over the 451.

Say we have two engines built with the same parts, E-Brock heads, say a solid roller in the .630 range and 270* @.050 with about 11.5 comp. in a Hot Street A Body with 4:10 gears, just for example.

Engine Number 1. Being the 451 cu.in

Engine Number 2. Being the 470 cu.in.

How much more Hp is the 470 worth over the 451?

Will the extra money spent on the lower end of the 470 be justified in the extra performance over the 451?

Just wondering, PeteTheKiller
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  #2  
Old 01-05-2002, 09:45 AM
warlockpowerwagon warlockpowerwagon is offline
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How are you making the 470?
The 451 is a stroked 400 using the 440 crank?
the bigger of equal build-up is more powereful. There are pros and cons arguable on every board. I do not have experience with either, but am planning on a 400/440 crank build-up this summer. Mostly because I have an old 440 and several 400's, and a freind with a machine shop. Supposedly the 451 will rev a little quicker (arguably) and the 470 would have a little more torque. HP? maybe 20-30 more in the bigger block. IMO
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  #3  
Old 01-05-2002, 10:58 AM
jelsr jelsr is offline
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This will be interesting. With the 470 you gain displacement but lose rod length and have heavier pistons. The 451 is smaller but has long rods and lighter pistons. Personally I would prefer the long rod, 1.8 vs 1.67, & lighter piston, 524gr vs 562gr (Ross) over the displacement advantage of the 470. I think personal preferences will make a greater difference than the performance capabilities. With the advent of 2.2" (BB Chev) journal rods in Mopar lengths and longer, offset grinding could offer some unusual combos.
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  #4  
Old 01-05-2002, 11:56 AM
TL TL is offline
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I am building an engine for a street car, pump gas. Always wanted a 470 Indy sr combination. May settle for a 451 because of cost. I have solid roller cam thats to big and harland sharp rockers. Will have to trade cam, but am wondering what rpm limit ly rods will have with KB pistons. I know bigger is better for street but I like the sound you get at about 7000 rpm. Heads are 915 that have been ported buy Hennsley. How high do I dare rev this?
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  #5  
Old 01-05-2002, 01:22 PM
Jims451 Jims451 is offline
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In theory they should make about the same peak HP, just the smaller 451 would need more revs (higher RPM.)
The 470 should have a bit more torque in the lower RPM range.
For me the cost difference (about $1,000) did not justify the extra 19 CID of the 470. I used the extra money saved to put into a good fuel system, head porting, exhaust system, ignition box, converter, slicks, etc...
I think it was worth it as my 451 has beaten some 500+ cid engines running simular heads and cam.
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  #6  
Old 01-06-2002, 02:46 PM
phoenix phoenix is offline
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Default 451 vrs. 470

Assuming useage of aftermarket rods and pistons, the 470 can be built on a "high rod ratio" genre using a 7.100" Eagle rod and an off the shelf J.E. SRP piston(1.625 comp. ht.) originally intended for the low deck, but using an RB 440 block. If you prefer the "high ratio engines" this is a consideration. When 451 vrs 470 using a low-deck configuration, typically the 470 provides earlier peak torque/hp curve, however all things being equal, not quite as "flat" and forgiving. Also the "chevy 2.200" journal has shown approx. 15 hp gain on 528" motors due probably to reduced brg. speeds/parasitic drag /oiling etc. however I have no test data on 470's but the gain should be there.
When deciding "which" engine to build it is important to explore many things in order to understand the characteristics of each to do accurate comparisons of your needs.
A "general" factor for horsepower that can be used when using the same head on different engines/ assuming everything is well matched/"right" for each engine(cam, intake, carb etc.) is to take peak flow X .2575, X 8cyl.'s. example; Roller cam, .600"flow@331cfm/.650"liftflow@340cfm/.700"flow@348cfm averaraged equals 339 cfm X .2575 = 87.4 X 8 =699 H.P. is acheivable. Obviously a smaller engine would have to rpm. harder and use a suitably longer duration cam to get there etc.
Sorry if I'm confusing the issue, only trying to provide some possibly useful info/areas to explore.
One more thing to the formula, Obviously as solid cams spend more time/duration at lower lifts, it is important to factor and average flows there as well. Flow your heads and factor according to your cam. Remember, Horsepower is a function of head flow regardless of engine size. The same head on a bigger engine just moves the events around/lower. WE then try and move 'em up again with other pieces, but the peaks will usually remain very close! That's why flow is such a big factor,
Good luck I'm out
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Old 01-06-2002, 11:56 PM
B1 B1 is offline
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why not build a low deck 499 cid? take a mopar 4.150 crank with 400 mains and the 440 rod and ross or venolia piston and you have mega torque and good rpm capability. even with the edelbrock heads this would make impressive power, but i would have the E heads ported. they will make about 35 more hp when ported correctly! and make sure you use a good intake like the original B1. they have adapter/spacers for that intake to be used on the stock flange, it will gain you an additional 45 hp! its a little costly, but they look SO intimidating. Brian
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  #8  
Old 01-07-2002, 03:54 PM
TL TL is offline
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I may have shot myself in the foot. A neighbor built an engine for his pulling truck. Ran it one year, got 2nd in points, then switched to a Chevy at 600 cu. I bought his 440, cheep enough, but its not what I need. 440 block,crank, Brooks rods, 12:1 compression, 700 lift roller cam lifters and rockers, Millidon gear drive, pan, and swinging pickup, 915 heads ported by Hennsly, Enderl mech. F.I. hat on Wiend tunnel ram. I thought I could use the heads and valve train, then sell the rest. A couple buyers ago I began to wonder if this will work. Engine looks like new but it is still here. By now I may have had my street engine built. If I start over with some LY rods on a 3.75 stroke and KB pistons, will this stand the rpm it takes to pump all the air a good set of ported 915 heads can flow if the cam is big enough not to be the limiting factor in a pump gas street engine, pain in the neck street engine, but none the less a street engine capable of a 1000 mile road trip on occation. I guess I need to sell this puller engine to someone with a drag car either way. See you in the classifieds.
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  #9  
Old 01-07-2002, 04:38 PM
451Mopar 451Mopar is offline
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If you start with the ported 915 heads, if done correctly, they should flow about 280 CFM @ 0.600"?
In theory tha air flow of the heads will limit max HP to about 575 HP @ 6,000 RPM with a 440 cid engine.

The old standby cam was the MP 292/0.509" and using around 10:1 compression the 440 should make 500+ HP. This setup was documented back in the 1980's and is pretty common.

With the newer high rate of lift cams, and 1.6:1 ratio rocker arms you can lift the valves quicker and faster to take more advantage of the cylinder head flow above 0.500".

For example the Hughes HE3038BL cam is fairly mild in duration (only 230/238 @ 0.050") but has 0.549"/0.572" valve lift using the 1.6:1 rocker arms.

As for the rods, these engines usually run the stock rods after being inspected, resized and using good rod bolts.
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  #10  
Old 01-08-2002, 12:54 AM
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FuryusVIP FuryusVIP is offline
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Default qouteing some guys who know...

Some people say that unless you put good heads on a bigger engine, you are better off building a 440, give or take .030-.060.

And by good heads I mean Indy S/R's or 440-1, B1's or Edlebrocks. Why spin to 7,000 when you can have it live longer and makes more power if it's bigger. Just a thought.
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  #11  
Old 01-09-2002, 12:50 AM
mauve66 mauve66 is offline
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I saw some talking about Indy motors so I don't know there combos. The ones I've seen were from Muscle Motors out of Chuck Senatores' book "Big Block Mopar Performance".
They are:
451- base stroker
474- step up to a real race motor, which was designed for the highest flow capabilities of the aluminum head (stage6 I think)
although he suggests a solid cam
496- with the aftermarket crank will notch up the cost. 650HP/600 ftlbs for the street
850HP/650 ftlbs for the strip
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