Quote:
Originally Posted by Cliff R
Keep in mind that I dyno tested my iron intake against the RPM (port matched) and 455HO (re-pop) intakes on the 428 engine mentioned earlier in this thread.
The iron intake made 497hp, RPM 491hp, HO 487hp. There were NO OTHER CHANGES done for those dyno pulls. Even though we LOST power putting the bigger/taller RPM on an 440cid engine with KRE heads (260cfm), 10.6 to 1 compression and 236/242 @ .050" custom ground HR cam with nearly .600" lift I see folks ditching factory intakes for the RPM on engines making a LOT less power. Not to mention having to "cobble" up the intstall 9 times out of 10 to get it under the hood, especially with factory Ram Air and Shaker cars.....FWIW.
|
Good info cliff, can you comment on why the HO intake was down 10hp from the iron? I thought they were basically the same intake just the HO is made from aluminum?
I have read from rocky rotela's testing that the SR replacement HO intakes made after the original production HO intakes had a shorter plenum floor that can affect power some... do you know if the HO you tested was a SR or original production?
I ran a 1969 iron intake ported by SD on my E-head OF cam 467 that did low 11's, then switched to a SD ported production HO I found for the weight savings & nicer looking, didnt notice any loss at the track or street but also no gains, runs pretty much the same. I realize 10hp probably wont show up at the track due to other variances from different days, just curious what your thoughts are on the 10hp loss for what should be identical intakes.