new heads for my 1641

[MDmanx]

Last night, I picked up a set of brand new DP heads from my buddy, for next to nothing. They are from so cal imports, and have 40mm intakes and 35.5 exhaust.

What are these heads, and will they fit my 1641?

If so, what is a good cam and rocker combo?

Thanks -Brian

oh yeah, dual kadrons and a quite pack turbo muffler, if that helps.

[RIS]

They might fit, but it depends if they have been bored. You need stock bore heads.

Is this going in a Manx? What compression are you going to run? Gears? Need this info before suggesting a Camshaft.
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[MDmanx]

Ive already got the 1641. It has stock heads on it right now.

Yes its going in a manx, and the r&p is 4.12:1

I'm not sure what the compression would be w/ these heads, but High test pump gas is ok.

I hope this helps.

Thanks -Brian

[RIS]

Verify the head bore of the newheads before you tear into your engine. Are these just big valve heads, or have they been ported? SoCal has some decent looking round ports that I remember seeing in the magazine ads. If they aren't ported you won't be very impressed by just bolting them on.

Once you tear into the engine you'll need to measure the deck height and combustion chamber cc to determine the compression ratio.

http://www.aircooled.net/gnrlsite/resource/specgeninfo/calcs.htm

If you'r going to split the case to install a camshaft, and you find the heads aren't stock bore you may as well upgrade the pistons to whatever the heads are. 90.5 or 94mm, 1776cc and 1915cc respectively.

As for camshafts if you stay 1.1:1 rocker a Engle W-110 with about 8.5:1 compression will give a nice balance of bottom and top-end power. But, in a light Manx I wouldn't be afraid to put an W-120 in it with 9:1 compression - add some 1.25:1 rockers to this last mix and you'll be very impressed.

Bigger vents in your Kadrons will make the most of these changes.
_________________
Richard Sedoris - VW Performance & Machine - Youngstown, OH
http://rismachine.tumblr.com/
YouTube: https://m.youtube.com/channel/UCfTBCG4I61iVm_ROc8OAuOQ
Instagram: @rismachine

[MDmanx]

That is very informitive. Thanks RIS.

what/where is the measurement on the head for bore size.

The main bore size around the combustion chamber is roughly 3.700 inches.

no porting. yet.

[vwracerdave]

3.700" converts to 93.9mm wich equals 85.5mm pistons.

If it were me I wouldn't bother tearing apart a good running 1641 just to replact stock heads with big valve heads. The HP increase won't be that much. I would just put those heads on the shelf and start collecting parts for a 1776 or 1914.
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2017 Street Comp Champion - Thunder Valley Raceway Park - Noble, OK
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1997 Sportsman ET Champion - Thunder Valley Raceway Park - Noble ,OK

[MDmanx]

[vicsvw]

Agree with not much difference. Heads make very little difference on motors 1835cc and smaller. The biggest difference is when the home builder does a bang up job of Port & Polishing, Then 99% of the time they run worse then the stock heads. Mistakes Common Mistakes Made Building Motors <> http://www.1800vw.bizhosting.com/mistakes.htm
Head Torquing info & Picture <> http://www.1800vw.bizhosting.com/headtorque.htm

[1955ccbug]

The heads are brand new right? I bought a set of heads from so-cal imports a couple years ago and found that they were 041 castings with 40 x35.5 valves but they left the 39mm seat in and just plopped a 40mm valve in. Didnt notice until I tried to lap the valves in and wasnt getting much. So make sure you lap the valves in.