Some new results for my 455.
08-17-2011, 11:40 PM
#21
Sweet build bro, the torque is what really shows on your build. I had alot of the same issues and just worked through them to get where i'm at. Looked like you did the same and came out with a winner! Hopefully you can join the 600+ to the rear wheels club. It ain't easy let me tell ya 
09-13-2011, 07:19 AM
#22
I find it very interesting that we have very similar engines, almost the same displacement, (except mine has a smaller bore, longer stroke) I have less cam duration (251 @ .050"), we make almost identical power, but my engine with a Fast 102 makes peak power higher at 6300-6400? That tells me your cam is either advanced too much (mine was a 115 lsa on a 114 icl) or that Harrop is still restrictive on that size engine even after porting. I also find it interesting that I lost 100 lb/ft of torque going from engine dyno to chassis dyno (630 tq vs 530 tq), yet Stage 7 made 630 tq at the tires, that would suggest 730 tq at the crank, just doesn't add up in my mind.
Thanks for sharing, and sorry to the OP for the highjack!
BTW, I've seen 502's make less than 700 hp, you would be getting it done to make 800 hp on pump gas with a hyd roller cam and would require something like a Mast intake or a Holley LS3 intake with dual TB's and some large heads flowing over 400.
Thanks for sharing, and sorry to the OP for the highjack!
BTW, I've seen 502's make less than 700 hp, you would be getting it done to make 800 hp on pump gas with a hyd roller cam and would require something like a Mast intake or a Holley LS3 intake with dual TB's and some large heads flowing over 400.
I also used 1 7/8", old style Kooks from 2005. I am getting 2" now with the newer style merge on them. So it did not have big dyno headers on it, just my old faithfulls from my 412.
I may or may not lose torque with the bigger header, but it will likely carry a little better up top. My power curve and rpms look identical in shape to Stage 7s, just 40-50 hp lower. I have a 6speed so I hope it only loses 85-90hp, but it is making 70hp more than it did with a smaller cam.
So I am happy.If I make the assumption that Stage 7 made 750hp fw, and use 457ci/468ci x 750hp, it gives 732. So I am off by 27hp, which is just 3.5%.
We all know dyno's vary too, so who knows for sure.
What I really like about the Harrop is the throttle control and idle qualities. Much different than my Fast 90 was. I like to make the car turn even more than I do drag racing.
I know for a fact the Harrop does not flow well as cast. We gained nearly 40cfm with some porting and throttle shafts. Still only at 330cfm after all that.My motor is not in the same league as these other big cube motors. It has lots of good parts, makes pretty good power and with loads of mid range torque. It should make a good streetable motor.
Last edited by RAMPANT; 09-13-2011 at 07:48 AM.
09-14-2011, 09:30 AM
#24
I would think I will need 2" to even approach the flow of the 245s exhaust ports. Let alone your nitrous version. The intake side is the strong point of the Mast head, with the extra 30cc's that is not surprising though.
In fact the order should be placed by end of day for the new headers.
It seems a number of places have dyno headers which are far bigger than the ones actually going to be used. Where I went, they only have SBC and BBC stuff so we used my 2005 Kooks headers that do not have a high velocity merge, but only the standard header collecter with the spike. They are in perfect condion no dents or anything, but it seems the Merge does help make a little more power.
Brian, which headers do you have?
Your motor did carry the torque a little longer than mine, but was lagging 30ft.lbs in the mid range. Top and bottom of the 3500-6500 were nearly the same.
I also think a little tuning will fatten up my 4.3k-4.7k range. It got pretty rich in there. I noticed that Stage7's tune did the exact same thing and same place.
In fact the order should be placed by end of day for the new headers.
It seems a number of places have dyno headers which are far bigger than the ones actually going to be used. Where I went, they only have SBC and BBC stuff so we used my 2005 Kooks headers that do not have a high velocity merge, but only the standard header collecter with the spike. They are in perfect condion no dents or anything, but it seems the Merge does help make a little more power.
Brian, which headers do you have?
Your motor did carry the torque a little longer than mine, but was lagging 30ft.lbs in the mid range. Top and bottom of the 3500-6500 were nearly the same.
I also think a little tuning will fatten up my 4.3k-4.7k range. It got pretty rich in there. I noticed that Stage7's tune did the exact same thing and same place.
Last edited by RAMPANT; 09-14-2011 at 10:12 AM.
