Billy, with the gearing that I had it was turning 5000 RPM every time I got on the freeway. I could get to the bottom of the ramp right quick but topped out at 60mph at some 5000 RPM.

I cannot tell you what the real horspower is of my 5.7Gi -- but I will tell you it gets on plane very easily with 12 people on board

There was a comparison done by Boating Mag some years ago of the two engines. My memory is that they found little difference between the two and that their conclusion wasn't disputed by VP. Save some money and get the Gi.

MIKE

Just the sticker might be even cheaper.

Had mine ported, picked up 100 HP at 5,000RPM, far more torque judging from the throttle response, but my heads were a major choke point as the induction and exhaust had already been improved.

I would not advise anyone to blindly port their own, without some good guidance. Easy to actually make them worse (as well as grind into a water jacket and make them useless) by not having an idea what you are doing.

Biggest thing is smooth rounding of the short side of the turn into the valves, to get the air to follow the turn instead of breaking off and litertally, killing flow at half the valve. That and removing any other odd bumps, lumps, and casting flash.
Too big is bad for your RPM range too, unless the engine is up-sized too.

BTW, polishing has gone away, as it has been found that excessive smoothness actually hurts air flow. The surface boundary layer is actually thicker draging against a polished surface, effectively making the port smaller. The best is the light surface roughness left by the sanding drums while still fairly coarse.

Lowrider, it's been said that Vortec heads for small blocks flow so well, and are already so thin casted that porting isn't necessary, and you can grind to much away, very quickly.

That is definitely a hazzard. Can't claim to know a thing personally about Vortec heads, as, running a big block, have never dealt with them.
I personally sought advice, and consultation (as well as work) from a preofessional head grinder, and, beyond my guidance for what I wanted to end up with, and my aplication and engine build info, I left him to his business, and was VERY pleased.

I would advise anyone who has not ground on heads, or at LEAST been told a great deal by someone grinding on your "other" heads, to give them to a pro before trying to port your own.

The Vortec heads are IMO, from all I have heard, a definite improvement, and possibly the best mid-RPM (like boats run) small block Chevy head available, and as a stock head, reasonably easy to find, at a good price, if undamaged.
A VERY GOOD upgrade part. Even so, prob. only worth 30 or 40 HP alone, unless other things have been upgraded already, or are part of the plan.
Harder to find performance manifolds for them I think, but then again, I have not looked arround. I may be mistaken here.

You can find ANYTHING you want for a big block Chevy, especially the old Mk-IV, The Gen VI not too bad, The Gen V, I'm not a fan of, for several reasons, including aftermarket parts availability.

Now, unlike most folks here, I have run mine well beyond that 5-grand limit, and for lengthy periods of time.

Think we howled her 5,400 for 4 minuites minimum chasing down a friend's Taylor 923 I/O (yea, I know, but it's still a Taylor, and Damien's a good guy), over at least 4 miles, then down into the glass of a deep cove too. Great time. Beautiful lake (Ouachita Arkansas).

So far I limit my 5,900 RPM nitrous runs to 30 secconds or so. LOL

My power peaks at about 5,500RPM, and I have the right impeller cut (prop guys consider this as "prop pitch") to allow me to use all that power. I don't have a gear-change in a drive to worry about tho, direct drive here, 1:1. Extra RPM not a problem to a jet, till you get close to 7-grand.

Thus, as noted in here earlier, considering power upgrades, keep in mind your intended operating RPM. MOST (but not all by any means) power upgrades will increase power all over (if done properly), but will do the most at higher RPM (the big blocks are somewhat (but only partially) an exception to this). If the higher RPM is a problem for the drive, re-consider how to increase power. Most of your engines (in stock form) are safe to 6,000RPM or more, BUT, the limiter is valve float from weak stock springs (that and the rev-limiters some of you all have). :-]