Re: 512 low deck on the dyno
[Re: AndyF]
#2955833
08/20/21 10:17 PM
08/20/21 10:17 PM
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Joined: May 2009
Posts: 511 Temperance, MI
68 HEMI GTS
mopar
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mopar
Joined: May 2009
Posts: 511
Temperance, MI
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Any more details on the combo Andy?
68 Dart GTS "HEMI" 10.30 @ 131 pump gas street car 3780# 69 Roadrunner 511 six pack 10.92 drive to track street car
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Re: 512 low deck on the dyno
[Re: AndyF]
#2955899
08/21/21 08:37 AM
08/21/21 08:37 AM
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Joined: Jan 2003
Posts: 10,010 Frostbitefalls MN (Rocky&Bullw...
gregsdart
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I Live Here
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Frostbitefalls MN (Rocky&Bullw...
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Pump gas street/strip deal. What else would you want to know? Compression, rockers, pushrods,rings, pistons, head flow, valve sizes, cam type and lift, did I miss anything?😁
8..603 156 mph best, 2905 lbs 549, indy 572-13, alky
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Re: 512 low deck on the dyno
[Re: gregsdart]
#2955919
08/21/21 10:23 AM
08/21/21 10:23 AM
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Joined: Mar 2003
Posts: 9,100 Rogue River, OR
Jeremiah
master
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master
Joined: Mar 2003
Posts: 9,100
Rogue River, OR
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Stop tempting me to EFI the dart. I already have the O2's, fuel system....and my 1050AN doesn't like my 451 unless the n20 is activated.
Is this a 4.25" stroke/6.535" rod/2.200" journal combo?
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Re: 512 low deck on the dyno
[Re: gregsdart]
#2955934
08/21/21 11:12 AM
08/21/21 11:12 AM
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Joined: Jan 2003
Posts: 31,046 Oregon
AndyF
OP
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OP
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Oregon
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Pump gas street/strip deal. What else would you want to know? Compression, rockers, pushrods,rings, pistons, head flow, valve sizes, cam type and lift, did I miss anything?😁 Heads are out of the box,
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Re: 512 low deck on the dyno
[Re: Jeremiah]
#2955935
08/21/21 11:13 AM
08/21/21 11:13 AM
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Joined: Jan 2003
Posts: 31,046 Oregon
AndyF
OP
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Oregon
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Stop tempting me to EFI the dart. I already have the O2's, fuel system....and my 1050AN doesn't like my 451 unless the n20 is activated.
Is this a 4.25" stroke/6.535" rod/2.200" journal combo? A Sniper 4500 would bolt on your combo fairly easily. I think it is a 440Source rotating assembly but I'm not positive. Parts have been hard to come by recently so the engine shop uses what they can find.
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Re: 512 low deck on the dyno
[Re: 440Jim]
#2957812
08/26/21 10:34 PM
08/26/21 10:34 PM
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Joined: Oct 2009
Posts: 248 near St Petersburg, FL
Lifsgrt
enthusiast
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enthusiast
Joined: Oct 2009
Posts: 248
near St Petersburg, FL
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Very nice, thanks for sharing. Would like to know CR and more cam/lifter/rocker info, thanks.
B3 1969 Charger R/T SE, 440/727 with 3:91s running 11.07@120
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Re: 512 low deck on the dyno
[Re: 440Jim]
#2957836
08/27/21 12:06 AM
08/27/21 12:06 AM
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Joined: Jan 2003
Posts: 31,046 Oregon
AndyF
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Sounds like it gained 30 hp with the injection system. Those OTB TF270 heads are pretty good.
Is the low rpm due to the conservative (low duration) cam? Goes with the CR. Maybe, hard to say what is causing the peak to be where it is. I've chased it around a bit with the 270 heads on 500 inch short blocks and my guess is that it is inherent in the design. A professionally ported intake can move the peak up a bit but more duration or more lift doesn't seem to move the peak up very much. Dwayne might have some thoughts on the subject but I don't know if he has actually made the modifications and successfully moved the peak RPM up with these heads. I tested a lot of cam profiles and bunch of rocker arm ratios with these heads. What I found is that they only want so much. A bigger cam doesn't automatically move the peak RPM up nor does a bigger cam always make more peak power. 264/268 might seem like a small cam but if the cam is much bigger the power drops off. In my pump gas 470 a cam with 270 duration made less power than the 264/268 so it was pretty touchy about how much duration it wanted. This equation would change with more compression but not as much as you think. I have a customer with a high compression 505 running TF270 heads and with a 280 duration cam it makes 750 hp in the 6500 rpm range. I think his cam is too big but that is what his engine builder told him to go with. Some people might want more power at a higher RPM but I think a lot of people would be happy to be able to make 700 hp with OOTB parts. Sure is a lot better situation than it used to be. I think a person could make 800 hp with the TF270 heads but my guess is that the valve job would need to be changed. I think the TF valve job is the key to 700 hp and the barrier to 800 hp but I don't know that for a fact.
Last edited by AndyF; 08/27/21 12:11 AM.
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Re: 512 low deck on the dyno
[Re: Lifsgrt]
#2957838
08/27/21 12:13 AM
08/27/21 12:13 AM
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Joined: Jan 2003
Posts: 31,046 Oregon
AndyF
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Very nice, thanks for sharing. Would like to know CR and more cam/lifter/rocker info, thanks. CR is around 10:1 and the cam is the same Comp 264/268 that I've used in the last few builds. I don't know what the rocker arm ratio is and it doesn't really matter anyway. 1.5, 1.6 or 1.7 will all make the same power in an engine like this. Higher ratios just work the springs harder.
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Re: 512 low deck on the dyno
[Re: AndyF]
#2957921
08/27/21 09:57 AM
08/27/21 09:57 AM
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Joined: Jan 2003
Posts: 14,504 So. Burlington, Vt.
fast68plymouth
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So. Burlington, Vt.
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Imo, the 700-750hp range is the sweet spot for the TF270.
To get beyond that, I think it’s a situation where the port area is trumping the flow numbers.
The interesting test would be a TF270/SRcnc295/440-1cnc325 shootout. The caveat is that the Indy heads would really need to be gone thru to get the valve job situation comparable between all the heads.
The intake flow at .700 lift would be pretty close between the 3, with the intake port volume getting bigger as you moved into the Indy heads, along with the exhaust flow and exhaust port size.
I think on something like a 540, and targeting 800+hp, you’d find it’s easier to get there with the bigger Indy heads.
For sure, the TF heads would still win the “bang for the buck” award.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: 512 low deck on the dyno
[Re: AndyF]
#2957977
08/27/21 12:07 PM
08/27/21 12:07 PM
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Joined: Jan 2003
Posts: 14,504 So. Burlington, Vt.
fast68plymouth
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I Live Here
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Looking at it another way, if you had a typical high CR bracket race 540 with some Indy heads on it, and it was making solidly over 800hp......... and you swapped the heads for the TF270’s......... I would expect there to be a noticeable hit to the HP, along with the upper end of the curve falling off quicker.
But....... that’s purely speculation on my part.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: 512 low deck on the dyno
[Re: fast68plymouth]
#2957988
08/27/21 12:38 PM
08/27/21 12:38 PM
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Joined: Jan 2003
Posts: 16,928 NC
440Jim
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To get beyond that, I think it’s a situation where the port area is trumping the flow numbers. I was going to post/ask that the lower RPM peak of the TF270 on the 511ish CID engine may be due to port volume. But Dwayne pretty much summed it up. For a 500-540 engine, 700-750 hp at a nice low rpm goes to the TF270. For more hp, more port volume would help those size engines. Expecting the peak RPM to go up with it Too bad they are basically out-of-stock everywhere.
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Re: 512 low deck on the dyno
[Re: AndyF]
#2958027
08/27/21 03:40 PM
08/27/21 03:40 PM
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Joined: Jan 2003
Posts: 14,504 So. Burlington, Vt.
fast68plymouth
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I Live Here
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So. Burlington, Vt.
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Tough trying to get someone to let you experiment with their new heads....... but it would be interesting to see how the EFI responded to a slightly larger throat diameter and 50* seats.
If it was in fact a “street/strip” vehicle, I’d probably sacrifice a few peak ponies for some better manners when the exhaust is closed up by spreading the lobes out a bit.
68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123 Dealer for Comp Cams/Indy Heads
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Re: 512 low deck on the dyno
[Re: AndyF]
#2958932
08/30/21 08:15 AM
08/30/21 08:15 AM
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Joined: Jan 2003
Posts: 4,057 Shelby Twp. Mi
HardcoreB
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Shelby Twp. Mi
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I would expect the same thing. Putting a TF270 head on a 800 hp engine would most likely turn it into a 750 hp engine. I think the TF head is perfect for a stock block bracket guy. If you have a stock block then you don't really want an 800 hp head since you'll crack the block. So a super nice CNC head that delivers 700 to 750 hp right out of the box is a perfect solution. Guys who have stepped up to aftermarket blocks should also step up to a head with more capability since there is no reason to limit themselves to 750 hp. ... Well-put!
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