I am curious how much my factory exhaust manifolds might be holding my 1976 360 back.

Here are the specs:
  • Stock bottom mid-70's 360
  • Factory 2bbl was rated at 180hp @ 4,000 and 290ftlb @ 2400
  • Milled [63cc] 2.02 J-heads, somewhere around 9.3:1 compression ratio
  • Edelbrock Performer RPM intake
  • Comp Hyd Flat Tappet, 0.470" intake lift, 0.480" exhaust lift @ 270/280 duration
  • Comp 901 matching valve springs
  • Stock rockers
  • Holley Sniper EFI
  • Stock exhaust manifolds with factory 2>1 single exhaust (2-1/4")


The truck runs decently well up to about 5,300rpm and it starts to fall off quickly thereafter. The cam and intake should pull pretty well up to 5,800, but I have a feeling my manifolds disagree.


I am not looking for a race truck, just something that is fun to cruise around in, how much are those factory exhaust manifolds holding me back at the top end?

1972 Barracuda - 5.7L Hemi, T56 Magnum 6spd - https://www.facebook.com/GoodysGotaHemi
2020 RAM 1500
[img]https://i.imgur.com/v9yezP9.jpg[/img]