<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}-->Sorry to bring up a dead topic but I am having an issue.
I recently ported a set of GMPP<!--td {border: 1px solid #ccc;}br {mso-data-placement:same-cell;}-->
https://mechanicguides.com/best-383-stroker-kit/ fast burn heads, for a friend of mine, that are going on a 383.
I had a 383 sitting in the shop that had been dynoed with a different set of heads, so I offered to dyno his heads on it to see the power potential of his heads, and to compare to the heads it had already been dynoed with.
We first dynoed his new heads with everything just like the 383 had already been dynoed with. Then we changed out the cam to the cam he plans on running in his 383.
The engine is,
4150 braswell carb,
ported motown intake with 1" spacer,
GMPP fast burn heads with 2.02"/1.56" valves with a finished volume of 210cc. (were GMPP vortecs)
1.7/1.7 shaft rockers
flat top pistons with a comp. of 11.5/1
4.031 bore x 3.75 stroke
1 3/4 x 1 7/8 step header, 3" collector
1st cam dynoed = comp cam 236/248 108 lsa .380in/.367ex lobes.
2nd cam dynoed= Howards shelf cam 255/261 108 lsa, .400 in .413 ex lobe
The 3 columns listed are with the Howards cam at 102*/105*/108* ICL.
When we switched to the bigger cam, peak TQ rpm went up 400-500 rpm, but peak HP rpm was very little higher than with the small cam.
Why? What’s the limit to peak HP rpm on this engine?
What would you change if looking for more power, but no more rpm?
What does the results of these 3 cam position pulls tell us about the engine/cam?
I realize there will be info wanted by some, so just ask.
I can post a pull with the small Comp cam if needed.