FLH versus FL Heads

[steve_wood]

So my vin is 56FLH****. The casting numbers on my heads are:

16704-56 (front)
16706-56 (rear)

Are these FLH heads or just plain ol' FL heads? Palmers talks about 16700-56 and 16701-56, but no mention of the casting numbers on my heads.

For what it's worth, the ports do like pretty smooth, like they've been ported and flowed, but without anything to compare with I'm just guessing.

Comments anybody?

[1950Panhead]

FLH introduced in 55, same head casting, ported and polished for FLH.
Jerry.

[steve_wood]

So the casting number are the same for FL and FLH?

[1950Panhead]

Yes

[cdndewey]

I believe there was a change in the valve springs also. But not 100% sure, as I recall reading something about that about 25-30 years ago.

[RUBONE]

FLH springs have higher seat pressures than FL. The originals are marked with a paint dot.
Robbie

[Hog54]

So my vin is 56FLH****. The casting numbers on my heads are:

16704-56 (front)
16706-56 (rear)

Are these FLH heads or just plain ol' FL heads? Palmers talks about 16700-56 and 16701-56, but no mention of the casting numbers on my heads.

For what it's worth, the ports do like pretty smooth, like they've been ported and flowed, but without anything to compare with I'm just guessing.

Comments anybody?

Mine are ported and smooth too,but mine are 16700-56 and 16701-56.

[58flh]

THE heads are the same as far as vale size----IF they are smooth inside the ports Somebody did this not the MOCO!---IF they had to remove every casting nerd --NO ONE COULD AFFORD TO BUY THE BIKES!. FLH has Hierseat-pressue as RUBONE mentioned!,Reason being the cam is a hier-lift & the comp. ratio is 8.5 to 1. THEY were meant to be solo riders,& footcluth handshift set-up! SO in a sense HDs. FLHs are the hotrod motor to put it in a lame way!---Someone def. cleaned-up the ports--When I did mine -(58flh),I removed alot of bumps & snot!,Just for better flow,cause everyone knows that pans dont flow very good!-Headwise.--Thats the main reson people were putting shovel uppers! FOR MORE FLOW=MORE POWER!----RICHIE

[kitabel]

Palmer: "FLH had a polished and flowed intake port for much better breathing"

[john HD]

i beleive i have a piece of mid '55 sales lit that reflects the polishing.

of course, since i moved i cannot find it.

do you really own something if you don't know where it is? (that's what my dad always said)


john

ps, my plain jane '55 FL heads were pretty smooth to begin with.

[steve_wood]

I'd love to see a side by side comparison of FL versus FLH ports.

I'll post some photos of mine (with part number).

Anybody else got pictures?

[steve_wood]

Here's a picture of the rear head intake port. Casting number 16706-56

[Cotten]

Folks,

I have a relatively unmolested '55 FLH on the bench, and the intake ports are indeed "polished".

....Cotten

[steve_wood]

Picture?

Casting number?

More polished than the one shown above?

[kitabel]

In case everyone has not read any of the answers: it's the same casting number.