Here's a CamQuest comparison between stock port OEM 990's and out of the box Dart Pro 1 310 heads using my blower motor as the platform.
The 990's seem to do a good job of providing flow and delivering HP/TQ with this build - 671 blower @ 8psi, 427 ci, 8:1 forged, hydraulic roller 252@.050, .612 lift, 110 LSA. I know folks have done extensive port and bowl work to make them flow better, bit with what results I don't know, as I have not done that.
These heads are certainly old technology and have a limit on how much Int/Exh flow they will provide. Comparing them to a set of Dart Pro 1 Aluminum heads (for example) is an eye opener. The published flow numbers tell the story. Below are flow numbers and a chart comparing the heads I'm looking at with my current 990's. Note that I had to do some extrapolation on the 990 flow numbers to fill in some gaps in the original data. I think tho, that the data below is pretty accurate.
Really a huge difference in performance, especially for my blower motor. I pretty much peaked at 612 hp / 561 ft/lbs in CamQuest with these 990's. Same build but with these Dart heads, CamQuest showed 743 hp / 601 ft/lbs. Big difference between them.
Now, having said all that, it really comes down to your application. What sort of horsepower do you need, how will you use your ride, and what is your budget like ? A pair of out of the box assembled Pro 1's run between $2,500 to $2,900 dollars, depending on how you dress them up.
How fast do you want to go ?
Head Comparison - OEM 990's to Dart Pro 1 2.25/310's
Moderator: John_Heard
Head Comparison - OEM 990's to Dart Pro 1 2.25/310's
1969 ProStreet Camaro RS Best 9.75@139 1.46 60'
Blown 427 BBC, TH400 w/Brake, Back-Half Ladderbar
Narrowed 12-Bolt, 4.10 Gears, Spool, Moser 33 Spline
http://www.marsh-racing.com/harrys_camaro-1.htm
Blown 427 BBC, TH400 w/Brake, Back-Half Ladderbar
Narrowed 12-Bolt, 4.10 Gears, Spool, Moser 33 Spline
http://www.marsh-racing.com/harrys_camaro-1.htm
Re: Head Comparison - OEM 990's to Dart Pro 1 2.25/310's
I have basically an LS 6 motor, when I bought it, I pd 3500 bucks, and got everything, I just had to put it together, it originally had LS7 Pistons / GM 180 cam. I switched the pistons to TRW LS6 replacements, and that killed the GM 180 LS7 Cam, The car with the ls6 pistons and comp ls6+ camshaft, has run 12.01 with the exhaust open and launching at 2500 rpm any higher and I spin.
This past winter, I embarked on a project to put weld in subframe connectors and formed rear frame rails in my car. way more project than I wanted. so now the spring schackles are moved 6 inches inward, and instead of trying to modify the wheel wells, I just put the tubs in. So now I have the room to rum bigger rims, but don't want to buy them until I narrow the rear end.
So back to the motor, I still have the LS7 pistons / cam, springs and lifters. My plan now is to freshen the bottom end up I was thinking stroker, but want to see how fast the LS7 can go, I want to switch it to E85, to I can still go to cruise ins. I know this is old technology stuff, but I already have it.
The whole package I think was a good deal, I got the four bolt block w/the green/purple dabs of paint on the front(not sure what that means) a High Perf 4 bolt block, GM 990 heads, dimple rods, pistons, rings, and everything from intake to oilpan.
This past winter, I embarked on a project to put weld in subframe connectors and formed rear frame rails in my car. way more project than I wanted. so now the spring schackles are moved 6 inches inward, and instead of trying to modify the wheel wells, I just put the tubs in. So now I have the room to rum bigger rims, but don't want to buy them until I narrow the rear end.
So back to the motor, I still have the LS7 pistons / cam, springs and lifters. My plan now is to freshen the bottom end up I was thinking stroker, but want to see how fast the LS7 can go, I want to switch it to E85, to I can still go to cruise ins. I know this is old technology stuff, but I already have it.
The whole package I think was a good deal, I got the four bolt block w/the green/purple dabs of paint on the front(not sure what that means) a High Perf 4 bolt block, GM 990 heads, dimple rods, pistons, rings, and everything from intake to oilpan.
I can't wait for race season, this has got to be the year.
Re: Head Comparison - OEM 990's to Dart Pro 1 2.25/310's
Sounds like a great combination and it sounds like you're having funLs7camaro wrote:I have basically an LS 6 motor, when I bought it, I pd 3500 bucks, and got everything, I just had to put it together, it originally had LS7 Pistons / GM 180 cam. I switched the pistons to TRW LS6 replacements, and that killed the GM 180 LS7 Cam, The car with the ls6 pistons and comp ls6+ camshaft, has run 12.01 with the exhaust open and launching at 2500 rpm any higher and I spin.
This past winter, I embarked on a project to put weld in subframe connectors and formed rear frame rails in my car. way more project than I wanted. so now the spring schackles are moved 6 inches inward, and instead of trying to modify the wheel wells, I just put the tubs in. So now I have the room to rum bigger rims, but don't want to buy them until I narrow the rear end.
So back to the motor, I still have the LS7 pistons / cam, springs and lifters. My plan now is to freshen the bottom end up I was thinking stroker, but want to see how fast the LS7 can go, I want to switch it to E85, to I can still go to cruise ins. I know this is old technology stuff, but I already have it.
The whole package I think was a good deal, I got the four bolt block w/the green/purple dabs of paint on the front(not sure what that means) a High Perf 4 bolt block, GM 990 heads, dimple rods, pistons, rings, and everything from intake to oilpan.
1969 ProStreet Camaro RS Best 9.75@139 1.46 60'
Blown 427 BBC, TH400 w/Brake, Back-Half Ladderbar
Narrowed 12-Bolt, 4.10 Gears, Spool, Moser 33 Spline
http://www.marsh-racing.com/harrys_camaro-1.htm
Blown 427 BBC, TH400 w/Brake, Back-Half Ladderbar
Narrowed 12-Bolt, 4.10 Gears, Spool, Moser 33 Spline
http://www.marsh-racing.com/harrys_camaro-1.htm
Re: Head Comparison - OEM 990's to Dart Pro 1 2.25/310's
If you keep the LS7 cam it should be at least 1/2 second faster than the old set up.
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