home porting

[nova_172]

doin some porting on my head at home and i cant decide wether to cut the valve guides bk or leave em, also in the bowl of the inlet port there is like a swirl chamber should i cut this bk 2.
thanks

[Jules]

I'd be inclined to leave that there as it helps the air and fuel mix.

[burgo]

and leave the valve guide otherwise the vavles will wear kwiker

[Stuart]

get a book by "david vizzard" regarding ford sohc engine modding. since the gm head and ford head were designed and made in the same factory in spain, the stuff applies to the gm heads too ;-)

[m.d.]

yeah that vizzard book is the dogs if you can get hold of it, go for the one on the ohc engines tho as there is loads out.

i ported my own head and it has made a load of difference, its not that hard either.

the way i did it was to first get a set of manifold gasgets and fix them to the head with a couple of nuts and washers on the head studs, you can now MATCH port the ports to the shape of the gasget. now make everthing as smooth as possible with the die grinder so you have nice smooth bends etc. also completly take away the casting arround the valve guide. (leave the valve guide in at first otherwise you end up going down its hole too much) on the valve side of things just grind the valve seat out untill you get to the mark where it used to seal. this is a good guide to how big you can go. to finish off get a small flapper wheel and polish it all up. (not too shiny tho as you will get running problems)

on the exhaust ports you may go through the casting into the water ways but dont worry. carry on untill you get the best shape you can, then get the wholes welded up and gind the welds back down to shape. (to get a good shape this will happen apparently)

here is a pic of my inlet to go by
http://www.cruisesouthwest.co.uk/modules/Gallery/albums/album53/100_0178.jpg
http://www.cruisesouthwest.co.uk/modules/Gallery/albums/album53/100_0179.jpg

[burgo]

lookin gd m d

[m.d.]

its taken me about 3-4 hours just for one port. lol if not more.

its all worth it tho when you see the power figure difference. especially seeing as tho im getting only a few horses less than a b+ cylinder head for less than 100 quid, and ive only been doing it for a year.

[Stuart]

bear in mind that is way way way more important to have all ports flowing the same(similar) ammount of air than to get huge gains from any one particular port ;-)

[m.d.]

very very true mate. it can also cause uneven stresses on the block and especially the crank if the ports are different