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Discussion Starter #1
2005 Fatboy,
Andrews 37 cam
Port heads "BigBoyz"
98" big bore kit with 10:1 pistons.
Should I have 1.90 intake vales done? If so what are the advantages and does exhaust valves need to be enlarged also?
Looking for pro's and con's of having this done. The head's are at the shop now.
 

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Bean at BigBoyz is the right man to answer your question, just call him and find out, he is a good guy to help you.
Armin
 

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Discussion Starter #3
Bean at BigBoyz is the right man to answer your question, just call him and find out, he is a good guy to help you.
Armin
I called him and he said to ask people on line. He didn't want to up sale me. Told me to research it myself and get back with him. So I'm reaching out to the group.
 

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Not really needed on a 98 unless you plan on spending a lot of time in the 6500 rpm range. There would be some advantage to getting a set of later 103 heads and then having them CNC'd. They can be had pretty cheap these days. For a given amount of flow, less work is required on the 06 on heads because of the improved intake port shape.
 

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Give me any year twin cam head and I will get it to flow and work well. You can't just pop a 1.9 vslve in.. it takes port changes to get it to work and peak tq happens at 3400 with peak power at 6000. It takes a 1.9 intake valve at 98" to go there and it will be right at 105 / 110. Put a 10 degree bigger cam and half a point compression and another 10/5 come up. Now you need a bigger tb and injectors, there is always a constraint in hot rodding. Sometimes that isn't anything bolted to it like the budget.
 

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But how much more performance do you get with a Andrews 37 with the bigger valves and porting as compared to just porting? I could see a different cam choice but a 37 is not high lift where I would think the valves would be making benefits. Maybe a 57, Just curious, been thinking of changing my cam to a 37 too.
 

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Porting with 1.9 valve and stock exhaust 7-10hp 5tq. Stock valves a few horsepower and when guys claim more it is from added compression. What i report was a back to back test on a 96" same cam compression, no other changes but fixing the tune, same dyno
 

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If you want to spend the money on a larger valve with the expectation that you may gain some performance, then do it.
 

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If nothing else, it should make your bench racing sessions a little more interesting.

What were the plans when you sent the heads off? This question should have been decided before they were in the mail.

And what do you consider more performance? It probably wont rip your arms out of their sockets, if that's what you mean. Do you mean measurable, or just how it feels? Do you have plans to take the bike to the strip to see if more performance shows up there? That would be kind of hard to do if you don't have a before to go with the after.
 
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