Intake For 468 BBC

[alteredu]

You might consider buying a 454R for a Dominator with an adapter for the 950, so you can change over in the future...

[vortecpro]

Hey everyone I haven't posted here in awhile, but now am having trouble finding answers on a suggestions for which intake to use on my motor. BLock is a 454 .060 over with four bolt mains. It has:

-Steel GM crank
-Eagle H beams with L-19 bolts
-SRP forged pistons with a tight quench (.038 quench making it 10.3:1 Compression)
-990 Casting Heads with little to no work done
-Comp Solid Roller Marine Grind 285CR-8 with comp roller lifters
-Can't remember the PN off the top of my head for valve springs, but they are appropriate to run to 7500 + rpm, so nothing light
-Dart intake
-Quick Fuel Q-950

This was just a motor I bought until I decide to build a bigger one and thew it together with the parts I could find to complete the build. I run this combo on 91 octane pump gas with no issues with detonation (due to tight quench I'm thinking) Combo makes 620hp from my calcualtions spinning it to 7200rpm. Car is a 69 Camaro weighing 3600lbs with me in it and runs high 10.90's at 122-123mph. I also drive the car on the street occasionally. Maybe 10 Times or so a year.

Now for the kicker. Putting it together I knew the dart intake had abnormally small intake ports which was odd. On a tight schedule I bolted it on as it was, and made a mental note that I would check it out later. Well its been two years of good running and I finally decided to pull it off and deal with it. It turns out that the intake is an oval port Dart instead of a rec port!! No wonder they looked small. I feel like I am giving up some power in this area, although I'm sure this whole time it wasn't bad for tourque. So question is, what do you guys think? Which rec port intake should I bolt on? I'm thinking of picking up a 454-R Edelbrock as it seems to have good results, thinking the dart rec port version might be a little big. Let me know what you think, and if there are any other suggestions for cams, that would be good as well.

Please dont take this wrong. Good information is sometimes hard to come by on the internet, 123 MPH is 515 HP @ 3600 pounds in your given conditions. I believe with a 4200 RPM converter flash a rectangle port air gap or performer RPM with a 1 inch open spacer would be faster. At the same time I would get after those 990s and make a converter change. Good luck.

[MileHighMan]

Something that baffels me about combos like this,,, and others as well,,,is why is it necessary to rev a motor like this to 72-7500 rpm at the shift point????.....My car went the quickest and fastest shifting at about 65-6600.......Dan.

[mitchmc]

Hey everyone I haven't posted here in awhile, but now am having trouble finding answers on a suggestions for which intake to use on my motor. BLock is a 454 .060 over with four bolt mains. It has:

-Steel GM crank
-Eagle H beams with L-19 bolts
-SRP forged pistons with a tight quench (.038 quench making it 10.3:1 Compression)
-990 Casting Heads with little to no work done
-Comp Solid Roller Marine Grind 285CR-8 with comp roller lifters
-Can't remember the PN off the top of my head for valve springs, but they are appropriate to run to 7500 + rpm, so nothing light
-Dart intake
-Quick Fuel Q-950

This was just a motor I bought until I decide to build a bigger one and thew it together with the parts I could find to complete the build. I run this combo on 91 octane pump gas with no issues with detonation (due to tight quench I'm thinking) Combo makes 620hp from my calcualtions spinning it to 7200rpm. Car is a 69 Camaro weighing 3600lbs with me in it and runs high 10.90's at 122-123mph. I also drive the car on the street occasionally. Maybe 10 Times or so a year.

Now for the kicker. Putting it together I knew the dart intake had abnormally small intake ports which was odd. On a tight schedule I bolted it on as it was, and made a mental note that I would check it out later. Well its been two years of good running and I finally decided to pull it off and deal with it. It turns out that the intake is an oval port Dart instead of a rec port!! No wonder they looked small. I feel like I am giving up some power in this area, although I'm sure this whole time it wasn't bad for tourque. So question is, what do you guys think? Which rec port intake should I bolt on? I'm thinking of picking up a 454-R Edelbrock as it seems to have good results, thinking the dart rec port version might be a little big. Let me know what you think, and if there are any other suggestions for cams, that would be good as well.

Please dont take this wrong. Good information is sometimes hard to come by on the internet, 123 MPH is 515 HP @ 3600 pounds in your given conditions. I believe with a 4200 RPM converter flash a rectangle port air gap or performer RPM with a 1 inch open spacer would be faster. At the same time I would get after those 990s and make a converter change. Good luck.

Hmm.... Really?? I guess I am running in 3500 ft air and same with anyone else around me, maybe this is the difference vortecpro? I know I have told a lot of people when I used to work at the shop what kind of power they are making. And have been accurate when compared to dyno results almost 100% of the time with the calculator we had there for it. This knowing the dyno was actually very conservative compared to many others. Maybe I'm wrong, maybe I'm right. I don't want to turn this into one of those arguments, becasue when people used to come in and try to tell me there 350 with iron heads makes 500 hp, it really ticked me off haha. So no harm no foul it doesn't really bother me either way.

And Dan, it is entirely possible that my tach is out by a couple hundred rpm. That being said, I would not rev it that high (on my tach) if it did not go faster along with lower E.T. I am not just revving it for the fun of it. If it was not necessary to go faster, I would not rev it that high. Shifting at 6600 (on my tach once again). I will only run 118mph and 11.20's.

[vortecpro]

Car hooks with zero wheel spin. Old traction bars from who knows what, worn out leaf springs, but it works. Almost pulls the front wheels off the ground (you could maybe fit a piece of paper under them, but still counts, haha) with nothing except drag shocks on front. So until this doesn't hook any longer, I won't change it. Oh and this is all through the stock 10 bolt with the 4.10 gears. I know, I know. It is destined for failure. But until it does, I'm good with it.

And maybe your right, 620 might be a touch high, but a hair over 600 should be accurate. I used to have access to a mph to hp calculator that was very accurate in most cases, and I think at 120mph or 121mph it was around 595hp?

I don't think a rec port single plain will kill tourque that much in the 4200 rpm range. Will it?...

The step is so huge from the intake to the head, I just do not see it being good for any sort of power. It HAS to be creating some turbulance which is in turn killing some of the potential torque this intake is made for. Again, no expert here. Just trying to picture it in my head.

How do you turn 7000 plus RPM and run 123 MPH with a 4.10 gear? Any TQ you lose @ 4200 is too much, as evidence by the high MPH to ET ratio, theres 3 tenths in making your car leave alone. Optimistic HP calculators are not any help in your quest to go faster. 515 HP in 3500 feet DA, 3500 feet DA would be about 4 tenths from sea level conditions 29.92 baro. I can see that engine combination making close to 620 corrected HP on the dyno, but trick is to close the gap between corrected dyno HP and actual track HP

[Ted Gerstenslager]

While just about any pump gas engine will turn 7000-7300 RPM most will make less power with more RPM.
As an example a 572"Marine engine from 10 years ago with 9.8 , a cam with 256 degress @.050, fully ported aftermarket Iron heads w/ 2.300 1.900, Dart rectangular intake with a Dominator made 757 @ 6000. Dropped like a rock after 6K.

Revision of the combination with oval port heads made into small rectangular port w/ about 7/8 radius, and Dart oval port intake w/ 7/8 radius and same dom, same camshaft, made 17 more and the peak went to 6200.

Your combo suggests it would continue to like the oval port manifold, but the Dart has a lot of plenum volume and the entrance to the runners is still quite large. I suggest you keep the oval combo but go to a Edelbrock 454 oval style, and leave it oval. Blend the upper radius of the carb pad to get rid of the sharp turn into the runners.

Your cam only has 254 @.050 and not a lot of lift so I doubt it is making power much after 6200. You probably have not even tried starting low in RPM and working your way up. Everybody thinks their BBC should turn 7000. Only trying low and working your way up will prove it.

[MileHighMan]

While just about any pump gas engine will turn 7000-7300 RPM most will make less power with more RPM.
As an example a 572"Marine engine from 10 years ago with 9.8 , a cam with 256 degress @.050, fully ported aftermarket Iron heads w/ 2.300 1.900, Dart rectangular intake with a Dominator made 757 @ 6000. Dropped like a rock after 6K.

Revision of the combination with oval port heads made into small rectangular port w/ about 7/8 radius, and Dart oval port intake w/ 7/8 radius and same dom, same camshaft, made 17 more and the peak went to 6200.

Your combo suggests it would continue to like the oval port manifold, but the Dart has a lot of plenum volume and the entrance to the runners is still quite large. I suggest you keep the oval combo but go to a Edelbrock 454 oval style, and leave it oval. Blend the upper radius of the carb pad to get rid of the sharp turn into the runners.

Your cam only has 254 @.050 and not a lot of lift so I doubt it is making power much after 6200. You probably have not even tried starting low in RPM and working your way up. Everybody thinks their BBC should turn 7000. Only trying low and working your way up will prove it.

Thank You!!!!....I was begining to think my motors were the only ones that made great power without ringing the shit out of them......Dan..

[mitchmc]

All you guys are correct, and I really should know better. My tach HAS to be going wonky on me. Because I am not making up stories when I say it will only go 116mph (or so) when shifting at 6000rpm, and just keeps going faster the higher I shift. Like in the 7400rpm range it seriously goes 123 or so. SO..... new tach in order because that cannot be right. Heck... for all I know I am only reving this thing to 5500rpm unknowingly. Shouldn't be that dramatic but who knows.

[MileHighMan]

All you guys are correct, and I really should know better. My tach HAS to be going wonky on me. Because I am not making up stories when I say it will only go 116mph (or so) when shifting at 6000rpm, and just keeps going faster the higher I shift. Like in the 7400rpm range it seriously goes 123 or so. SO..... new tach in order because that cannot be right. Heck... for all I know I am only reving this thing to 5500rpm unknowingly. Shouldn't be that dramatic but who knows.

My suggestion to would be to get your car on chassis dyno at least.....The place here only charges about $80 bucks an hour and it will tell you alot about your whole car.....Some don't agree with me about that,,but I feel it's money well spent...Also,, don't go crying in the corner because you did'nt get the h/p numbers you were wanting....Just use it as a tool and learn what you can........Dan.