Author Topic: 427 heads  (Read 542 times)

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rcianci

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427 heads
« on: August 01, 2020, 11:17:37 AM »
Im no 427 parts guy so I pose this question. What is the differenve between a 427 low riser head and a mediuim riser head.Intakes and exhaust heights? Overall height? Thx. Bob.

Hipopinto

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Re: 427 heads
« Reply #1 on: August 02, 2020, 05:58:17 AM »
Bob

There is a lot to learn about the 427 and all it’s variants!

I know very little but I will try my beat to help explain and guys if I’m am wrong PLEASE correct Me

The 427 Center Oiler was introduced in 1963 it featured low riser heads low riser heads actually have taller ports than “medium” risers

In 1964 ford introduced the High riser I believe it was on a center Oiler block as well but it featured a very tall intake port and a tall manifold hence the name

The “side Oiler” was a different block casting than all previous FE engines as all other types of FE engines are center oiling  designs

The 427 side Oiler block was introduced in 1965

Somewhere around 1965 I believe the medium riser hit the scene I may be wrong in this statement and if I am please correct me.

There is also the 427 SOHC (the rarest of the breed) and the 427 tunnel port

All of these combos have intakes to match them as well

There is a lot more I am missing but this is the place to find info

I hope this helps

Dave


cjshaker

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Re: 427 heads
« Reply #2 on: August 02, 2020, 12:04:31 PM »
Im no 427 parts guy so I pose this question. What is the differenve between a 427 low riser head and a mediuim riser head.Intakes and exhaust heights? Overall height? Thx. Bob.

Medium riser heads have machined combustion chambers where the LR heads are cast like nearly all other FE heads. The machined chambers are much larger than standard heads, so this is important when getting pistons. MR heads have larger valves than all other FE heads except for Tunnel Port and HR heads. MR heads have raised intake ports which are smaller than many other standard heads, but flow better due to port volume (velocity) and entry angle. Except for Tunnel Port and modified Highriser heads (port floor filled), MR heads are the best factory heads there are. The drawback is they're hard to find in decent shape, or haven't been milled to death.
Doug Smith


'69 R-code Mach 1, '65 427 MR, 2x4, 4-spd, 4.30 Locker
2 1965 Galaxies with 390s
1970 F-350 390
1958 Ford Ranch Wagon 390