Has anyone had any experience with QHP 510 heads? They are selling on e-bay and sounds like they know like their stuff. I have 95" jugs and pistons on the way and think I might try these heads. From the looks of it, they sell a ton of these but I don't hear too much about them.

 

Well, I don't know a thing about these people or their heads, but I can give you a stupid rant.

I had a 2005 Heritage with the S&S 510 gear drive cams which is basically what they say they are matching the flow to. They were awesome cams, designed to increase torque across a wide and flat band and they truly did.

I didn't have the bore increased. I just had an SE breather, Power Commander and V&H 2 into 1 pro pipe HS, which by themselves (stage 1) made a big difference. When I added the cams ($1,100) I could really tell another difference.

After adding the stage 1 and also the cams, I gained about 15 HP and 15 ft pounds of torque on the dyno. I gained a whole gear going uphill on "known" hills. In other words, when driving home at the same 45 mph up the same hill, I could be in 4th gear instead of 3rd gear without lugging down. Same for other situations.

The difference when riding 2 up was really noticeable too.

Note that they recommend these heads when using these cams or cams with similar specs. Are you planning on, or have you replaced your cams? IMHO you need the cams first. The heads won't do much good unless the cam opens the valves more and leaves them open longer. All of the porting etc. in the world won't overcome the restriction of a puny cam.

My experience and knowledge are limited to my bikes and years of hot rodding small block Chevys and not to any formal education. I had an EVO done with stage 1 and then later added an Andrews EV27 cam with the same good results as the above TC88.

I can tell you this. The shop that does my work is an independent with a dyno and some really good people. I got dyno readouts at every level.

The biggest bang for your buck is stage 1 which also costs the least. You gain good HP and torque for about a grand. Then you might pick up another 10 with a big bore for $xxx. Next, you might gain another 5 with cams for over a grand. Then you might gain another 3 with heads for another grand or more.

IMHO I’m tired of throwing countless dollars at my bikes when they run great with stage 1. Even though I can afford it, I’m just an average driver who finds a good running stage 1 1450 cc engine to be plenty, and to sound great.

Next, I might add cams for a little more power and for the lope at idle that sounds great too. After that, who am I trying to outrun?

My TC88 stage 2 with the 510 cams but stock bore and heads was pushing 95 ft pounds of torque from under 2000 to over 4500 rpm on the dyno. How much do I need?

Back to these particular heads, yes great porting and bigger valves can make a big difference. I’d ask for some dyno numbers on those heads before and after with the 510 cams and without the 510 cams. How much torque would you gain for the buck?

Remember, torque is the raw twisting power that gets you and your passenger and/or your bike away from the stoplight, up the hills and just generally all around lets the bike accelerate without revving it up too much. Horsepower is generally gained at higher rpms where most people don’t operate. Torque could be called the usable street power and HP could be, arguably, called a theoretical number “if you want to rev it up that high.”

You’re getting ready to dump some serious, never to be recovered dollars into your bike with big bore, cams and heads. Can you use or do you need or is it worth all of that money for that extra power in your every day driving style?

JB

 

I just double checked those figures and I was way off, sorry. I gained about 10 HP and about 15 foot pounds torque. It wound up averaging on dyno runs about 88 HP and 93 torque with the cams.

The torque curve was really flat - nice from just under 2000 rpm to just over 4500 rpms which is where most of us old guys operate. It was good from 1200 rpm to 1900 rpm. It worked great, but the flattest curve was from 19xx to 46xx.

Sorry about that, I said it would be a "stupid" rant.

I also forgot to mention that cams will decrease your effective compression ratio. If you're going with new cylinders and heads, you probably want to have some machining done or buy specific pistons to boost that cr a bit.

JB

 

Dam you sound like my builder, he installed 510 cam gear drive on my 2000 95 cc RG . He pritty much said in 1 sentence what you explaned in 13 paragraths. That was good keep the opinions coming. I say that because there are some that will argue to there grave.

 

All I really wanted was an opinion from members on QHP heads. Didn't mean to stir up any rants.