More power... But how?
 

Currently running stock '99 HP500's but I'm looking for more.Do I build what I have or do i sell while they're stock and buy different motors? So many different ways to go about it i just dont know what the most cost effective way would be. Find a pair of blowers drop compression and cam; raise compression and cam(na); buy carbed 575s/600s and build; buy professionaly built and dynoed non-merc motors? Surely someone has weighed the options. I don't plan on doing anything this winter due to the fact that this years budget is hanging off the back, but i'd like to have somewhat of a plan and a direction to head towards. Pump gas is an absolute must.

Thanks,
Riley

3 questions....

1 what drives do you have ???

2 How fast do you want to go ??

3 what is the budget ????

Big shaft #4s.id like to cruise 65-70.don't really care about wot.as far as budget it will depend power and platform.probably around 15-20k max.

whipples on those 500's

The absolute cheapest way to "cruise" 65 is to push the throttles til your running that speed and re-fresh more often.

With those drives you could bore/stroke to 540/555 and not worry about TQ. With about a 9/1 compression and good heads you should be around 650. Your straight bottom should top 80 WOT and stay within your budget.

Those "blue" merc motors are worth all the money. Sell them while there stock and worth more than a custom built dart block motor. Build a pair of 540's or 572's or look hard and find a nice pair that need to be freshened up.

I talked to Pier 57 today about repowering or trading up for more speed & if resale is a concern, was told stock merc power a + blue power ++ aftermarket - unless maybe Teague other big name but that would blow your budget. Randy

PROCHARGERS.... best bang for the buck.... my .02

you can easily make 750+ HP with your engines and prochcargers if you do it right.... my buddy has 509 with edelbrock heads and 525 cams, carbed with prochargers, pushes his 353 Formula to 107 MPH, never dynoed but its gotta be around 800 or so to push that baot to them speeds..I know you can make 700 with stock heads and such with em, even thatsnot bad, cost you a lot more to Build N/A engines to make 700+

The blower shop has a 10-71 complete kit specifically for the hp500.the guy i talked to said i can bolt them on and go? Bare minimum i would cam. But stock compression seems pretty high? Thoughts on this?

8.75 isnt too high for a low boost application. put 5lb's and innercoolers to them and you will have a great package.

Since you are from Illinois I would recommend calling Bill from Ateco. They are in Northern Illinois. Bill is a super nice guy and very knowledgable, not just going to try and sell you something. I put together my engines and had them dyno them. Bill had given me some suggestions on making more HP and also helped me out with some other problems I was having with temperature. Worth a phone call in my opinion.

Intercooled prochargers will make more power..

A 500HP carb motor really is not worth much today. Keep what you have, and improve them. Buying used performance engines is risky if you don't really know what is inside them.

Add some polished blowers, the right cam, serp belt system, nice headers, paint the blocks pretty, and have the valve and intake covers custom painted or wrapped to match the boat. IMO that set up with your drives in a Cig is worth way more than those 500hp carbs.

Adding alum heads or a chiller (or both) will make your engines more reliable at the cruise speed you desire.

http://www.whipplesuperchargers.com/...sp?ProdID=1159

12-13k bolt on and go for a pair. staying well in your budget

cant beat them

im pretty much sold on the TBS setup if the compression wont be an issue.$4300 a side complete less carbs and upgrade to a 525 spec cam.Which 525 though? efi or sc? And i talked to ateco at pier 57's open house this spring but i wasnt looking for more at that time. Seem like good people though.

if your going through the trouble of changing the cam call bob madara at marine kinetics and have him custom grind you a couple. 525 cams arent blower cams

Wouldnt the cam specs for a 525sc be a blower cam? i agree tho that a custom one based on specific setup would be best. but i dont know the cost difference between the two.

my bad.. i meant a 525efi cam isnt a blower cam. a 525sc is a 454... needs more cam for more cubic inch. the little more money for a custom grind for his application and the performance gains vs a off the shelf cam will be well worth the money... whats another 2-300 bucks when your spending 10k

Very good point.Whole reason i'm waiting til next winter is the motors will be out again for rebuilds.400hrs on them now, should be around 550 by next winter so cams are a no brainer with them being apart already.

Is 15-20k for the rebuilds and blowers, for both motors?

i do all my own work, and have a good friend that runs an engine/machine shop.$8600-blowers, $4000-fresh long blocks, $3200-carbs, $15800-total leaving $4200 for cams and misc if i go that route

Weld crane put 10:71's on his 500s last winter. No cam swap. Runs awesome. Pro chargers make great power but the torque is a bit peaky and higher up in the rpm range from what I have seen. With the big Ssm style props you will be running, planing may be an issue with pro chargers because they won't make enough torque to get the big wheels it needs for the top end swinging. Mild thunders buddy was going through this recently.

Exactly what i was told by the rep. Bolt them on and go. Wouldn't know what he ran for carbs would you?

I can call him tomorrow, pretty sure they are quick fuel 850s

The 525EFI cams will work fine a blower setup and much better than the stock HP500 carb cams.
The cam change and TBS 250's @ 5#'s of boost should put you in the 650hp range. You could run a single Dominator carb as well.

[QUOTE=lil red;3844942 Pro chargers make great power but the torque is a bit peaky and higher up in the rpm range from what I have seen. With the big Ssm style props you will be running, planing may be an issue with pro chargers because they won't make enough torque to get the big wheels it needs for the top end swinging. Mild thunders buddy was going through this recently.[/QUOTE]

I dont know if they have gotten better in recent years, but Prochargers used to be a PIA to install too. Def not for a beginner. Lots of modifying as far as brackets and moving things around....then once running, they were not easy to tune......but, done properly, they DO make power, no denying that.

I like the whipple better than Root (TBS). The efficiency is 25-20% better. You get an intercooler and fuel pump with their kit and it is only 2" taller than you current engine which should easily fit under your curretn hatch saving you at least 2k in glass and upolstery work for scoops. just my $.02

I've kicked around all of these ideas with prior boats. You're better off with the Whipple's. You could run those till it's time to rebuild then if you want to change the heads or cams, do it at that point instead of wasting the money now. You shouldn't have to change the cams and the compression is fine. You'll probably be able to clear your hatch as well. If you install 10-71's and intercoolers, you're going to be installing hatch inserts, and maybe scoops. Figure that into your budget. The only thing I'd be concerned with bolting those on are the condition of your head gaskets.

All good points.whipple makes good products but they're pretty proud of them.as far as the hatch that's minor.what im kicking around at the moment is putting the 525 cams in before i put the motors back in since im done with the other projects and run them like that for the season.then next fall refresh and bolt the blowers on.I've done a few searches but theres a discrepancy in the crane part number.

Keep an eye out on in the swap shop. You can pick up whipple kits for e decent price there.

I personally would build NA 540's out of your existing motors, turn key, and enjoy.

Next you need to figure out your hatch situation raised or scoops.

650-700HP going that route, and its gonna take some trick heads and a wild cam.

10-71's with chillers, 850-900HP. Still turn key with milder cams.

My blower motors start with a flip of the key. My buddies N/A carb'd engines do some cranking before they will start. Blower motors don't have to wait for vacuum to build to draw fuel in the cylinder. Setup properly they start and idle like a dream.

I say go blower. The 525EFI cam will work just fine with a roots.