043 mexican heads on 1776 project

[pau79]

Hello everyone,

I try to build my first engine. I'm going to set it up in a 71 westy.

The specifications are:
as41 case
90.5 mahle
40 webber double carburetors
bosch 019
engle 100 camshaft
genne berg solid shafts
original rockers
push rods crhomoly
valve springs and lifters engle
luk clutch 200mm
crankshaft cranks and original balanced flywheel.

the heads are a 043101375R mexico that have valves of 33 and 29 mm.
I am willing to put new guides, valves and valve seats to make sure everything is in order.

my question is if I keep the original valve measurements or I put some bigger ones for this engine configuration.

greetings

[Brian_e]

Those must be fuel injected heads?

I would do 35x32 for sure if you are sticking with a w100 cam. It might be cheaper for you to get a set of AA, or Mofoco, stock valve heads rather then paying to get those heads reworked.

Brian

[pau79]

Hello Brian,
I understand then that running with 33x29 valves is not an option. I'm going to compare prices on condition the 043 or buy a new AA.
thanks for your reply .
regards

[Brian_e]

It will run with the small valves, but those are 40hp size. You might as well stick with a stock cam if you keep the smaller valves.

Brian

[modok]

Far as practical experience, with carburetors, larger valve is better! When done right.
I actually prefer to use Fi heads as a base for installing larger vlaves, the small valve heads allows the most freedom to make the valve pocket and throat as good as it can be.

I'm not 100% sure why VW chose to use smaller valves with the fuel injected models. That IMO is the mystery!