pennies

[old Tom]

Does anyone put pennies in the heat risers anymore?

[Ronnieroadster]

The answer is yes.

[34fordy]

Why?

[TonyM]

People insist that only "wheat" pennies be used; not true--any pre 1982 penny is mostly copper.
No need for me to do this..
.
.
.

[tubman]

I don't buy into this program at all. Racing manifolds already have no carburetor heat passages; street manifolds do. If you're an all out racer, your manifold will take care of any fuel heating problems. If you want to run on the street, you will probably need manifold heat. I'm from Minnesota so I don't know if the weather in SoCal and surrounding areas requires it, but there are better ways of doing it (removeable pieces of shim stock that can be slid over the exhaust passages after loosening the manifold bolts).

Of course, "penny's" are traditional, so if your more concerned about a "hot rod" modification that can't even be seen over street manners, proceed!

[Ronnieroadster]

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Originally Posted by 34fordy

Why?

Doing so makes a slight change in the exhaust tone and as noted above is a small Hot Rodding tip that allows a cooler intake which run betters in certain modified application's.
Of course it defeats the cold weather warm up but in the winter most Hot Rodders are in the garage working on their rides so by spring time they can once again terrorize the common folk
Ronnieroadster

[Gene1949]

Back in the 50s I always chocked that wheat penny nonsense up to the anal-retentive kids. Those of us that were actually interested in carburetor heat/manifold hotspot tuning looked in mom’s garbage for a tuna fish can lid. We were too broke to afford stainless shim stock.
I helped an old circle track racer (static) balance a flat head using a gram scale, a file and 2 hacksaw blades set in groves cut in the top of an apple box. We did some crazy R&D because we didn’t know any better. We lived in the backwoods of Oregon where knowledge was in real short supply.
We broke a lot of stuff but thankfully we had a couple of sympathetic wreaking yards to the economic plight of some poor kids. A couple hours work would net you a couple of broken flatheads. Take ‘em apart put it back together with the best parts and you had a Saturday night special.

[Ol' Ron]

no!!
G

[Gene1949]

true stories, Ron. Swear to God

[tubman]

Originally Posted by Gene1949

true stories, Ron. Swear to God

I think Ron was answering the O/P's original question. Correct me if I'm wrong.

[Pete]

Pennies will always be a traditional way of increasing the "back off rap" of the pipes on a basically stock flathead engine with straight through type mufflers.

That hole gets welded up in an all out race engine along with much of the ports in that area.

[Joe B.]

For anyone, besides me, wondering what this penny mystery is about, here's a link to a great description in "The Flat Spot". https://myflatheadford.com/the-wheat-penny-trick/

[Flathead Fever]

That was a real thing. I live in SoCal and was told by some of old-time dry lake racers that were still around that they preferred to use the WWII 1943 steel pennies in the block, (I'm just telling you what I was told). It blocked the heat for cold startups from getting up into the intake manifold, but you didn't want that heat getting up there on a warmed-up race engine. You could buy intakes either with the heat riser ports or without them. If you already had an intake that had the heat riser ports and you wanted to get rid of them, you could plug the holes in the block with pennies. The reason many people still do this today on a street engine is it changes the sound of the exhaust. Take a look at many of the racing intakes on eBay and you will see that some of them don't have those centered heat riser ports on each side. It's something to be aware of if you're shopping for an intake.