cam choice

[Q5XX29]

Thank you.  60' times on a good run are 1.56-1.59 range. It launches great. Mph, disappointingly, is only 116-117. Maybe you have some idea why that might be?

Just curious.... what rpm are you shifting at ? and through the traps ?

Have tried shifting anywhere from 5900 to 6200, and it doesn't seem to make too much difference. Its my 20 year-old son's Charger, but I've driven it downtrack several times too. If I recall correctly, I thought it was getting fairly close to redline again going through the traps, because I remember thinking we couldn't go up much more than maybe 4.10s.. but now that I run the tire/gear calculator, with the 29.5" tall tires we run at the dragstip, it should be only at about 5350 at 117 mph, so could we be losing THAT much through the converter?  Sorry to the OP for the thread hijack.

I'm thinking your stellar 60ft times ? are coming at least somewhat at the expense of patent rotary flow/closer to lockup Convertor function of that Convertor in the Heavy car ?
just say'in....
FULL stall is 100% axial flow and 0% rotary flow in the Convertor....
and as the rear wheels turn faster and faster....
the Convertor should try to transmit more and more to the wheels as it reverses Torque Multiplication and approaches 3,4,5% ? axial flow and transmits 95% rotary flow ?
Don't SHOOT me for the readers digest version.... far more going on obviously just simplified for conversation.

No matter....
60 ft times are very important to E.T. at the Drag Strip because anything GAINED or LOST in 60ft time you can almost DOUBLE off or on to the E.T.
If you want MORE mph at the traps ?
the trick will be to finding a Convertor capable of more efficient closer to lock up at mph.... whilst still capable of the low 60ft times that YOU DO NOT WANT TO LOSE !
let me guess here....
any chance your Convertor is a store bought stocking unit and may be a little too loose for the Heavy Car ?
That said,
It can get pretty expensive opting for custom convertors trying for more mph and maintaining that all important to E.T. 60ft characteristic ?

IMO, 4.10's on the 29.5's is puss... stay there !

Thank you, I think you are right. I don't know if you saw my corrected post, after I realized that my drag radials were actually only 27.6" tall. Anyway, 3.91s on 27.6" tires, or if I did go up to 4.10s (which I think I still have the engine rpms for, before the end of the quarter) do seem to be a successful combo for me. The stall converter isn't a terribly cheap one- it is an FTI 3500 stall 9.5" billet street race non-lockup converter. Another thought I had is that the header size I have is probably a tad on the small size. I reused the hooker 1 7/8" ones I had previously on the car because they were still pretty new, but my engine builder said he found over 50 hp on my engine combo when he used 2 1/8" over the 1 7/8" headers. I dunno. Seems that BSB67 with his higher trap speeds using just factory exhaust manifolds does alright with those! But lots of variables. As stated, we seem to be getting ALL of the power to the ground on the launch, and have consistently crappy DA at our track, so all things considered we are very happy.  

[c00nhunterjoe]

2 1/4 tubes are pretty massive. I dont recall your build but ive seen best results with step headers in most race applications. Bsb67 (russ) running manifolds has a cam grind specific for the manifolds and even then, would stilm pickup alot with a longtube swap, but his build was specifically for him.

[Q5XX29]

2 1/4 tubes are pretty massive. I dont recall your build but ive seen best results with step headers in most race applications. Bsb67 (russ) running manifolds has a cam grind specific for the manifolds and even then, would stilm pickup alot with a longtube swap, but his build was specifically for him.

Sorry, I meant 2 1/8" headers, which I still thought sounded pretty big, but he said he dyno'd my combo with both and that's what it liked best. What you said about Russ' application makes sense, thanks.

(Edited my above comment to reflect the correct header size )

[Challenger340]

2 1/4 tubes are pretty massive. I dont recall your build but ive seen best results with step headers in most race applications. Bsb67 (russ) running manifolds has a cam grind specific for the manifolds and even then, would stilm pickup alot with a longtube swap, but his build was specifically for him.

Sorry, I meant 2 1/8" headers, which I still thought sounded pretty big, but he said he dyno'd my combo with both and that's what it liked best. What you said about Russ' application makes sense, thanks.

(Edited my above comment to reflect the correct header size )

I am curious around the 'criterion' used..... whereby the 2 1/8" Headers were described as BEST ?     Do you recall what primary tube length 2 1/8" was tested ? ?

[Q5XX29]

2 1/4 tubes are pretty massive. I dont recall your build but ive seen best results with step headers in most race applications. Bsb67 (russ) running manifolds has a cam grind specific for the manifolds and even then, would stilm pickup alot with a longtube swap, but his build was specifically for him.

Sorry, I meant 2 1/8" headers, which I still thought sounded pretty big, but he said he dyno'd my combo with both and that's what it liked best. What you said about Russ' application makes sense, thanks.

(Edited my above comment to reflect the correct header size )

I am curious around the 'criterion' used..... whereby the 2 1/8" Headers were described as BEST ?     Do you recall what primary tube length 2 1/8" was tested ? ?

Sorry, I am not sure. The engine was built a couple of years ago and still going very strong, after probably 25 dragstrip runs, and maybe 2000 street miles. I just recall telling the engine builder back then that I planned on re-using my 1 7/8" headers and he said that he tested this combo and it liked the 2 1/8" headers better than that 1 7/8" headers, to the tune of about 50 hp. Not saying that's true, but that is what he told me. He also told me that he tested my combo with and without a "super sucker" spacer under the carb, and I think he said it made 25 hp more with that, but alas, I cannot fit it under the stock '68 Charger hood with the M1 intake. I have some videos of this car posted a while back on my Instagram account if anybody is interested: dakota_gt is my username there.

[c00nhunterjoe]

In looking back and seeing that it is a 500" with a stock port window head, i cannot see how a 2 1/8 tube would pickup any, let alone 50hp over an 1 7/8 tube. On the 13:1 572 running heavily ported 572-13 heads, we use tubes that big. On my maxwedge port heads, the 2" step header has been the best so far. I would be very curious to see those dyno sheets.

[Q5XX29]

I was/am skeptical too, Joe. Just reporting what the engine builder told us. I never saw any dyno sheets. My engine was run in on an engine stand but not dyno'd. He estimated my power output should be around 560-570 crank hp, based on using this combo in several other builds that he had done. You can look him up, even give him a call to discuss, if you are so inclined. His name is Dustin Strong, Strong Performance in O'Neill, Nebraska. The engine work was all handled through a buddy of mine, pretty well known "Mopar Guru" around these parts, Brad Harms. Great guy. He recommended Dustin Strong to me, to build my engine. Apparently not long after he built my engine, Dustin's reputation went to $hit and he screwed a bunch of customers over. I was sorry to hear that, and figured if anything ever went wrong with my engine, I would be SOL, based on that knowledge. BUT- I've had nothing but excellence from this stroker he built for me. Hope that continues!