spark arrestor base
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I would like to replace just the flat base plate on my spark arrestor of my HP500 (carbs) engines with ones that have a radius, keeping the rest of the arrestors unchanged. Does someone make this?
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Got to Summit or Jegs and search K&N Stubstack. That is what you're looking for. They offer Stubstacks for all popular carbs AND for guys who are running a performance application, they even offer one for guys running Holleys with the choke horns milled off.
I'd guess you'd need to make a minor mod to the baseplate of your arrestors (open the hole in the bottom up).
Stubstacks are supposed to be good for some hp (15 they claim, but on what I am unsure).
I'd guess you'd need to make a minor mod to the baseplate of your arrestors (open the hole in the bottom up).
Stubstacks are supposed to be good for some hp (15 they claim, but on what I am unsure).
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Thanks mcollinstn,
I found them at Jegs, only problem is that they are made out of plastic that they say might crack if you tighten them down to much , I don't think that would be legal or safe. I then found K and N marine air filters with velocity stacks, $120. Anybody use these? Just looking for some "cheap" horsepower.
I found them at Jegs, only problem is that they are made out of plastic that they say might crack if you tighten them down to much , I don't think that would be legal or safe. I then found K and N marine air filters with velocity stacks, $120. Anybody use these? Just looking for some "cheap" horsepower.
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Cheap horsepower means nitrous.
I doubt you could change anything on the top of your Holleys that would reflect in a noticeable increase in RPM regardless of cost... Your holleys are matched fairly well to your combo and your stock flame arrestor is not particularly restrictive.
If you are running Gils, you *might* see 100 rpm if you swap to a $3800 set of tube-tops.
If you want noticeable performance increase on an HP500, then you will need a camshaft change (and it wouldn't hurt to have the heads pocket ported and the intake gasket matched). This will run around $700. Probably good for 200 rpm.
Nitrous will run $350 and will give you around 500 rpm (in a 175 hp state of tune). That's the best bang for the buck that you can expect (course a $40 refill is only good for 35 seconds).
Wish there was a better way.
A 1" phenolic open hole carb spacer is your best chance at cheap performance. It could show as much as close to 50rpm for you at a cost of $30 (plus your carb will stay cooler). If it doesn't help, you can make a nice hat out of it for your dog.
I doubt you could change anything on the top of your Holleys that would reflect in a noticeable increase in RPM regardless of cost... Your holleys are matched fairly well to your combo and your stock flame arrestor is not particularly restrictive.
If you are running Gils, you *might* see 100 rpm if you swap to a $3800 set of tube-tops.
If you want noticeable performance increase on an HP500, then you will need a camshaft change (and it wouldn't hurt to have the heads pocket ported and the intake gasket matched). This will run around $700. Probably good for 200 rpm.
Nitrous will run $350 and will give you around 500 rpm (in a 175 hp state of tune). That's the best bang for the buck that you can expect (course a $40 refill is only good for 35 seconds).
Wish there was a better way.
A 1" phenolic open hole carb spacer is your best chance at cheap performance. It could show as much as close to 50rpm for you at a cost of $30 (plus your carb will stay cooler). If it doesn't help, you can make a nice hat out of it for your dog.