Where can I send my heads?

[chiefmoose]

Looking for someone who does performance head work on a Briggs 18hp Vanguard twin. Multi-angle valve job, ported intake and exhaust, double springs and hd retainers, milled .030. Also looking for tips on pipes or a header for my argo response. Looking to increase performance, and still use my stock starter, and run 93 octane. I saw the other threads on the 18hp vanguard, but I live in BFE and dont have ANY resourses around here. Any help is greatly appreciated.

[Roger S]

I get the feeling you're in Canada. I can recommend someone in Ontario. Otherwise, Tennessee.

The problem for the response exhaust wise, is limited room for decent length primary tubes + a muffler. Do you have the Y shaped header pipe into the can muffler, or the later long round muffler up close to the engine.

[Holster]

Try huber performance in Saint Louis or extrude hone. Check it out online

[chiefmoose]

I am in AL, so tenessee wouldnt be so bad. I have the y-shaped header pipe. Any other tips on performance? After the exhaust I will drill my main jet. Do I really need mufflers?

[Holster]

mufflers are a must. Loss of back pressure means less torque!!

[Roger S]

Tennessee would be George at E.C. I would call him and see what he thinks about spending $ on the heads. They can do mild to wild. I did my own porting which was only blending the port and valve pocket rough castings, and radiusing the short side turns. No enlargement necessary. I havn't even done a "real" valve job, but it would be a good next step.

Exhaust: E.C. has header flanges and pipe kits, if you can fab. I suggest a 2 into 1 with an RLV silencer, through E.C. Primaries around 16". Micmac used them on his max4 exhaust build under this site's build threads. The silencer is probably a little bigger in Dia than the black grill on the argo.. The silencer added 1 hp to almost every header George dyno'd.

Back pressure is a misunderstood term. You can make changes to an exhaust and say "backpressure" did so and so, but having a positive pressure in the exhaust port of a 4 stroke when the exhaust valve opens hurts performance. That's what my stock response exhaust did to my built engine.

I'll be interested to see what your ideas do for power, although I'm still of the mindset of long rods/shaved pistons for compression. With a stock cam/compression release it probably wouldn't have any starter problems. You could use the octane additive I do and carry it in quarts. Rods/rings/gaskets around $330. BUT I would get George's opinion on on this paragragh as I havn't seen this combination run.

Remind George that we're CVT rpm limited to 3 or 4000 most of the time. You can tweak your cvt a little, also.