The overhead cam issue would have been settled years back, Ford had their cammer that they wanted to run on the NASCAR tracks, so Chrysler got wind of it and put a prototype DOHC Hemi (big time HP and RPM Potential) together, that Engine shocked Ole France when he saw it and he Hated Chrysler BTW, Bill swore they would never run those Motors in his racing, so we still see the 30 year old technology running there.
Now If Ford and Chrysler would have raced these, then GM would have stepped up or been left running last and this would be the norm today, But that ONE lunk-head put the kibosh on racing technology.. LMAO Chrysler called it the Doomsday Machine.


http://i41.tinypic.com/vhyko.jpg

Why doesn't Mercury put a blower on their dual overhead cam motor?

Offer both.

I think we are at the dawn of a better day for high performance boating. Merc has certainly made the nay-sayers realize turbos can and do work for marine apps (most said they wouldn't or don't work only a few years ago) and it's no secret turbos can make more power and can be more efficient. Once someone makes cast (not welded SS tube) water cooled manifolds and exhaust housings for the turbos readily available and at a reasonable cost, I suspect most will want to go this direction going forward... I know I will likely want to go that direction myself. It looks like Harden is committed to doing turbo kits and if they can do so using cast manifolds (rather than SS tubing) I think they will have a large market waiting with open arms to buy them.

Likewise, if well engineered DOHC heads can be retrofitted to existing BBC's at a reasonable cost, maintenance and top end rebuilds will be reduced drastically.

Not to metion that Hardin's kit includes exhaust for in the $12K range. If you need new headers for your 525, why not pay some more and get the turbo kit with the headers?

I can understand some people not wanting to mod their engines or even not wanting to go to FI, but beside that, is Hardin using SS or cast turbo manifolds??? If welded SS tubing I wouldn't use them with turbos!

Eddie,

Are you talking about this company or aare you aware of another ?

http://araoengineering.com/Chevy/chevybb.htm


Jon

Largest TVS is 2.3 liter, and while a car can make short burst to 18,000rpm, steady state at 18,000, with quick bounces off the rev limit would be the demise of the SC. The SC's are also not very over built for the constant throttle abuse. The heavier the rotor, the more rotating mass, the harder it is to live on quick accel/decel. I know of a few "marine" type applications that required massive redesign of the front drive system to make live in the constant abuse arena we call marine.

For steady state, lower rpms on SC's are always better for long life.

Jon,
Understood. But many have had failures in stainless exhaust. Heck, many have them without extra HP, so adding a few hundred degree's and pressure doesn't add to longer life.

Another example of packaging, as your system looks great, but would never fit in a dual motor side by side application. It would require mounting the turbo at the back and towards the centerline, then if its a bravo application, which most side by sides are, then there would be no room in the back. Packaging is truly one of the toughest task, as there are an infinite amount of variables.

I think I know which ones your talking about, aren't they still push rod based though? There is no question the DOHC can significantly make the BBC better, I wish a company like Dart, AFR, Brodix, etc. would jump on it but its one of those things that while many of us would do it, the mass numbers would probably shy away because of price and lack of experience.

Some of the things that can be done is amazing though, with the 5.0L Ford Coyote motor that has 11:1 compression, we adjust the cams to make the motor a "miller cycle" motor without ever changing compression, camshafts, spirngs or anything but the calibration.

If they still used pushrods I would have to assume they aren't DOHC engines but DOV engines using 32 valve heads. Which would mean they still use pushrods and rockers? Not sure how you could "convert" a BBC to truly be a DOHC engine?