Jakeoman Posted April 7, 2012 Share Posted April 7, 2012 I recently installed a set of blueprinted and ported 240cc 243 heads with oversized valves on my 1998 c5 corvette and wow! I cant tell which of a mod yielded more of a boost between my cam/UD pulley mod or this!! raised compression ratio to 10:9:1 with room to go for more with a different gasket, Apparantly 97-99 heads were the worst casting for the c5 corvettes ever made, im going for retune this week to see what kind of numbers i will put down but i can tell it will be stout! flow went from stock 806 castings which is around .207 cfm at .600 lift to a whopping .330 cfm at .600 lift on these heads. For all 97-00 owners that are lookin to go fast i reccomend a very stout set of heads, and even 00-04 c5 owners these would be a huge upgrade over stock as well (more for 97-00 owners)! You will need some wider tires for sure... my 275s can get sideways at 60mph no problem! haha Will post numbers soon but last my c5 put down 411rwhp with cam/intake/exhaust mods at azdynochip. hoping to throw down 460+ we will see! Highly reccomend this mod! What a kick in the pants! Parts added: Blueprinted and ported 240cc 243 heads with oversized valves out of bluepitt kustoms MSD coil packs Oil breather Coolant crossover Studded rockers ARP head bolts Link to comment Share on other sites More sharing options...
Bigfoot Posted April 7, 2012 Share Posted April 7, 2012 I had asked that question before and most said the gains would be modest at best. Interesting that you report differently. Link to comment Share on other sites More sharing options...
Big Poppa Posted April 7, 2012 Share Posted April 7, 2012 It's a combination. The parts feed off each other... Just heads, or just a cam, or just an intake... Modest at best. But when installed as a package, they make a huge difference. It's important when buying hot rod parts to buy them in conjunction with each other so it all performs to its best. Link to comment Share on other sites More sharing options...
Guest Sidewinder Posted April 7, 2012 Share Posted April 7, 2012 ^this Link to comment Share on other sites More sharing options...
Jakeoman Posted April 7, 2012 Author Share Posted April 7, 2012 Yes and my car currently has every stinkin mod (short of a stroker bottem end) that is possible on an LS1 lol... so yes the gains will be substantial... especially with my big ole cam Link to comment Share on other sites More sharing options...
LastC3 Posted April 8, 2012 Share Posted April 8, 2012 It's a combination. The parts feed off each other... Just heads, or just a cam, or just an intake... Modest at best. But when installed as a package, they make a huge difference. It's important when buying hot rod parts to buy them in conjunction with each other so it all performs to its best. Link to comment Share on other sites More sharing options...
Two Fangs Posted April 8, 2012 Share Posted April 8, 2012 Who did the work? I think 330 CFM out of these heads, especially at that port volume is a bit optimistic. Link to comment Share on other sites More sharing options...
philv Posted April 8, 2012 Share Posted April 8, 2012 Who did the work? I think 330 CFM out of these heads, especially at that port volume is a bit optimistic. he said they're BPK's heres a link to their CL add http://phoenix.craigslist.org/wvl/pts/2863517925.html Link to comment Share on other sites More sharing options...
Ted Y Posted April 8, 2012 Share Posted April 8, 2012 Who did the work? I think 330 CFM out of these heads, especially at that port volume is a bit optimistic. Actually, he said .330 cubic feet per minute. Link to comment Share on other sites More sharing options...
Two Fangs Posted April 8, 2012 Share Posted April 8, 2012 Ha ha, well in that case.... Link to comment Share on other sites More sharing options...
Jakeoman Posted April 8, 2012 Author Share Posted April 8, 2012 This guy has prob 20 set of heads on him... i took his best set that were not advertised on his list. Go big or go home! He will be doing some more port work in the future on some others set for all others looking for a set like mine! Link to comment Share on other sites More sharing options...
Jakeoman Posted April 8, 2012 Author Share Posted April 8, 2012 Who did the work? I think 330 CFM out of these heads, especially at that port volume is a bit optimistic. 243's have been reported to be able to go up yo .350-.360 cfm also... so .330 is stout but "optimistic" is not the right word for these. mine only had roughly 8-9 hours of hand port work, if your looking for a set around .350 range you will be paying close to 7gs on a set of heads that will undergo roughly 16 hours of port work... hardly worth the money imo Link to comment Share on other sites More sharing options...
Two Fangs Posted April 9, 2012 Share Posted April 9, 2012 These days, no hand ported head is worth the money. The inconsistencies from port to port and from set to set are just too great. CNC is the only way to fly. Glad you like them, but based on what I saw on the CL ad, they are nothing to write home about. There is more to life than port flow numbers, but I wish you luck if this is the avenue you have chosen. Link to comment Share on other sites More sharing options...
Jakeoman Posted April 9, 2012 Author Share Posted April 9, 2012 These days, no hand ported head is worth the money. The inconsistencies from port to port and from set to set are just too great. CNC is the only way to fly. Glad you like them, but based on what I saw on the CL ad, they are nothing to write home about. There is more to life than port flow numbers, but I wish you luck if this is the avenue you have chosen. "CNC" "TPS" they are all good companies but most are all hype. If your lucky enough to find a guy who has been porting for over 20 years you will find a gem. Anything that can give you better horsepower numbers on the dyno than the reputable "CNC" and "TPS" is worth writing home about. Considering you will pay those companies same/more than i did for a port not nearly as strong as mine. Its all about getting the most for our money! Just like supercharger or turbo kits, you can pony up the dough and buy an APS twin turbo kit and make 250 HP over stock and run efficient as hell, or buy the bottom of the barrel cheap STS kit and make around 200 and run a little hotter... all depends on how much that little extra power is worth it to you. Link to comment Share on other sites More sharing options...
Two Fangs Posted April 9, 2012 Share Posted April 9, 2012 CNC is not a company, well it may be, but it was not what I was referring to. CNC stands for Computer Numerically Controlled, and is a machining process. It uses a computer and a specially designed 5-axis mill and gives repeatable results to within one ten thousandth of one inch from port to port. Many years ago, hand porting was the only real means we had to enhance port flow characteristics from a set of cylinder heads. Today, with the decreased cost of CNC machining equipment, having a set of precision machined heads is well within reach of most enthusiasts. Hand porting is labor intensive, along with requiring the flowing of each cylinder head port and matching them for flow and velocity. With a CNC head, flow one intake and one exhaust port and get the whole story. My only advice to you is to be careful when looking at flow numbers, especially with a set of hogged out stockers. They truly only tell part of the story. Consistency from port to port in tumble and swirl as the air leaves the port, along with truly consistent flow and velocity gradients will produce the best results. And I hear you on the APS vs STS thing, man those shitty rear mount kits, what were they thinking when they designed those Link to comment Share on other sites More sharing options...
Grayeagle Posted April 9, 2012 Share Posted April 9, 2012 Guessin they figured the long .. longlong .. tubes wouldn't affect turbo lag .. much Or mebbe they figured they could sell a NOS kit to spin 'em up the first time the guy stepped on the gas and nothin happened till Tuesday. Always just looked plain wrong to me. Prolly had a good fuel-air mix by the time the air got to the intake tho .. LOL. As has been said .. it's always a systems approach .. I useda point an laugh at the guys who put an 850 Holly on a stock 289 ..an such Gotta have the rest of the toys to make it work well. -Frank aka GE Link to comment Share on other sites More sharing options...
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