ok guys need to know if i just need to scrap this and start over. I have a 454 block bored .030 over, 396 crank, and cast iron semi chambered heads oval port built to the gills. i do not know the specs of the heads yet as they are at the machine shop. i was leaning towards a 496 build instead of the 433. wanted to add a blower or supercharger and this is where i need the most help. i can get a 10-71 blower setup or an f2 procharger setup. can i run these with oval port heads? the guy with the 10-71 said to just run the rectangular port gasket. the guy with the f2 supercharger said i need rectangular port heads if i want to go past 700hp with the procharger and said that i cant use a rectangular port gasket on a oval port head with the 10-71. so my question is if i get the f2 procharger should i get rectangular port heads or can i run oval port heads with 8-12 lbs of boost. i will definately be getting a nice forged rotating assembly to hand forced induction. just want to know if its a waste of time and money to run forced induction with oval port heads. also said i have to run a small carb with oval port heads? thanks for the help guys.
454 block oval port heads/super charger???
67cam427
1 - 20 of 21 Posts
ok guys need to know if i just need to scrap this and start over. I have a 454 block bored .030 over, 396 crank, and cast iron semi chambered heads oval port built to the gills. i do not know the specs of the heads yet as they are at the machine shop. i was leaning towards a 496 build instead of the 433. wanted to add a blower or supercharger and this is where i need the most help. i can get a 10-71 blower setup or an f2 procharger setup. can i run these with oval port heads? the guy with the 10-71 said to just run the rectangular port gasket. the guy with the f2 supercharger said i need rectangular port heads if i want to go past 700hp with the procharger and said that i cant use a rectangular port gasket on a oval port head with the 10-71. so my question is if i get the f2 procharger should i get rectangular port heads or can i run oval port heads with 8-12 lbs of boost. i will definately be getting a nice forged rotating assembly to hand forced induction. just want to know if its a waste of time and money to run forced induction with oval port heads. also said i have to run a small carb with oval port heads? thanks for the help guys.
Joined
·
10,475 Posts
Before you worry about the heads you need to decide what type of power you want. The two different blowers will make totally different types of power. The roots blower is going to be a beast from idle to redline. The F2 is going to make less power down low, but lots more power up top. What will the car be used for?
I'm a roots blower junkie so my opinion would be biased. I will tell you that the shape of the ports on the heads doesn't matter as much as the flow potential. Since I am more of a small block guy I can't really tell you which way to go. I can tell you that low end torque with a roots blower is not a problem so I wouldn't be worried about running larger ports.
I'm a roots blower junkie so my opinion would be biased. I will tell you that the shape of the ports on the heads doesn't matter as much as the flow potential. Since I am more of a small block guy I can't really tell you which way to go. I can tell you that low end torque with a roots blower is not a problem so I wouldn't be worried about running larger ports.
thanks for the reply bud. sorry i didnt add more lol i knew i would leave some stuff out. just like to hit around 700-800hp or more with a nice amount of torque low rpm. mainly city driving with some highway driving and some occasional 1/4 mile runs. so i definately want more low end power i guess for street use. so i have a few options to go with. f2 or 8/10-71 blower, 496 stroker kit, or make it a 427 with 396 crank "433 with .030 bore".
Joined
·
10,475 Posts
For your goals I would lean towards a roots blower if you like that look. Your HP goal will not even be a challenge. You will do that without even trying with a blown big block. To be honest either size engine will get the job done. The larger engine will just get it done with less boost. I also think that goal can be made with either type of head. Just get your compression where it needs to be. If you go with an 8-71 which is big enough for the 433, or 10-71 for the 496 or larger, you will want the compression down around 7.5-8.0:1. With the 433 800HP is not out of the question. With the 496 800HP will be simple and 900 would be well within reach. Like I said before the low end torque will be absolutely nuts.
Procharged engines usually run a little more compression, and make more top end HP than a roots.
Procharged engines usually run a little more compression, and make more top end HP than a roots.
As far as the 10-71 - the intake ports on manifold really should match the heads - I'm not sure you would want to bolt a square port blower manifold on oval ports, very poor match would sure seem like it would impede flow and cost you power. For the money to build a solid blower motor, you should consider matching the heads. A set of Brodix or AFR heads would make your blown engine a true monster, I would lean more toward the raised exhaust port providing better flow. Remember even if you get a good buy on the blower the rest of the engine needs to be high quality or it won't last. Quality usually equals money. Blown BB's are not cheap!
I would lean toward the F2 for a few reasons. First, it does not stick through the hood and you can get away with a single carb on a blow through set-up. You can then get a matching manifold and not have to buy heads. Second is you can utilize an intercooler that will let you run a little more compression and timing - creating much more hp. Last, a little less low rpm torque will allow you to actually drive the thing on the street without flaming your tires every time you jump the gas. Traction in BBC cars can be difficult - a roots blown BB might make it near impossible.
Getting 700 or more hp should not be too hard. Lots of LS folks getting 650+ rwhp with Procharged 347's and D1 - with BBC cubes and F2 should very easily exceed your goals by a lot.
As with any other high powered build, you really need to take into consideration transmission, rear end, brakes, frame connectors, cage and safety items. Hate to see you twist a classic car into a pretzel.
I would lean toward the F2 for a few reasons. First, it does not stick through the hood and you can get away with a single carb on a blow through set-up. You can then get a matching manifold and not have to buy heads. Second is you can utilize an intercooler that will let you run a little more compression and timing - creating much more hp. Last, a little less low rpm torque will allow you to actually drive the thing on the street without flaming your tires every time you jump the gas. Traction in BBC cars can be difficult - a roots blown BB might make it near impossible.
Getting 700 or more hp should not be too hard. Lots of LS folks getting 650+ rwhp with Procharged 347's and D1 - with BBC cubes and F2 should very easily exceed your goals by a lot.
As with any other high powered build, you really need to take into consideration transmission, rear end, brakes, frame connectors, cage and safety items. Hate to see you twist a classic car into a pretzel.
whether i go forced induction or not i will be running a brand new ford 9" not sure what spline i need. comes with 31 but i can get bigger. New th400 built to handle atleast 1000hp. caltracs traction bars. already have disc brake kit. what kind of intake should i run with a f2 procharger? what size carb? so was the guy wrong for telling me and can not use oval ports with a f2 setup. he was trying to sell me some rectangular port heads. he made a good argument but i dont need 1500hp and believe with the f2 that i could still see 800+ horse on a 496 with oval port heads. if i did go with afr heads what size would you suggest?
Joined
·
441 Posts
+1. Listen to Royce.
The roots will be more fun on the street and at the cruise nights. Your car will become an instant crowd magnet. The centrigugal will be easier to go fast at the track as it will be easier to get traction/ put the power down. You also dont have all that weight on the nose screwing your weight transfer and you dont have to cut the hood. The centrigugal is more efficient than a roots blower and will make more horsepower, but will not make the low end torque that a roots blower will and low end torque is what you drive around the street on. I am a roots guy, myself.. as I am in it for the fun factor rather than racing championships.
The 433 roots engine will make an easy 750hp with a good build and ~12 lbs boost. You will have trouble not making 800hp with the 496 roots. Both the 433 and 496 centrifugal engines should be well over 800hp, with the 496 centrifugal able to surpass 900hp easily. With any of these combos, serious chassis considerations are in order to be able to make use of the power.
mike
Boost is a measure of restriction. A better flowing head wont make a huge gain in power it will just make the power at a more efficient/lower boost. You might have to run 3-4# more boost to achieve the power you would have with the lesser flowing head. When you compress air it creates heat, this is why I would suggest going with a more efficient/better flowing head.
This is especially important with a roots type charger with no intercooler to cool the compressed air. 10-12# of intercooled boost will make quite a bit of difference in power Vs 10-12# of non intercooled boost.
I like the Procharger set up due to the ability to run a large intercooler. This allows you to reliably run more boost with lower octane fuel and less chance of preignition. Its more efficient than the roots and when properly set up/dialed in you wont notice any boost lag at all on the lower end.
The F2 will be very loud though, it will sound like a commercial air liner is flying over your car everywhere you go... a pluss for me as I love the sound.
This is especially important with a roots type charger with no intercooler to cool the compressed air. 10-12# of intercooled boost will make quite a bit of difference in power Vs 10-12# of non intercooled boost.
I like the Procharger set up due to the ability to run a large intercooler. This allows you to reliably run more boost with lower octane fuel and less chance of preignition. Its more efficient than the roots and when properly set up/dialed in you wont notice any boost lag at all on the lower end.
The F2 will be very loud though, it will sound like a commercial air liner is flying over your car everywhere you go... a pluss for me as I love the sound.
how much boost would i make with the upper pulley at 48 and the lower pulley at 51? I will make sure to tell him i want the intercooler that comes with the 10-71 setup then. and just want to be sure on this i can run the oval port heads with a rectangular port gasket since the intake on roots blowers are rectangular port. that is what the guy from the blower shop told me.
A roots blower is positive displacement. Amount of boost will depend on engine size - 433 will have more boost than 496 for same pulley set.
What kind of intercooler comes with the 10-71? Putting an intercooler between blower and manifold is going to make a pretty tall set-up.
Correct me if im wrong but arent all roots type intercoolers water cooled?
It doesnt take long for that water to heat up and your no better off than if you didnt have an intercooler at all. They also require a resivior that takes up space and adds weight. There great for the drag strip but for street driving, cruises etc there of little benifit.
The air to air intercoolers for a Procharger set up are like an extra radiator in front of the car... no fluids, pumps, tanks and no maintenance. The air to air intercoolers arent the best heat exchangers in the dead heat of summer but at your boost level it will work fine. For someone looking to maximize there street driven pump gas friendly combo and wanting a car that they can drive anywhere/anytime the air to air intercoolers are the best option.
Dont get me wrong, I am no expert by any means... I have no personal experience with the roots chargers or roots type intercoolers.
Joined
·
441 Posts
Your boost is going to depend on more than just pulley ratio.. the blower size, weather the blower is stripped or not, blower opening design, loosnes of blower set up, engine displacement, in/ex head port sizes, cam overlap, exhaust back pressure, carb size will all effect your boost level. I do have a formula to estimate. An 8-71 on a 433 with that pully ratio (6.3% overdrive) will give you about 12.7 lbs boost (ball park). With that pulley ratio, a 10-71 and a 496ci will give you somewhere around 11 lbs of boost. It may be tight fitting the distributor with a 10-71 blower.. make sure you get a front offset blower with a small diameter distributor. An 8-71 with that pulley ratio on the 496ci would give you 9.2 lbs boost (ballpark) and well over 800hp...probably closer to 850hp with good heads without even having to go solid roller.
Those roots blower intercoolers cost over $2200 and raise the blower height significantly, so you see them more on boats than cars.
mike
Consider chemical intercooling if e-85 is not an option.Search water/meth inj systems for wot blasts.
Joined
·
10,475 Posts
Let's not get carried away with the need for an intercooler. at 12-14psi of boost you aren't going to need an intercooler, that is money wasted. you are not going to heat up the intake charge that much at that drive ratio or level of boost. Keep in mind a roots blower moves are VERY well it just doesn't compress air well. This is the difference between centrif and roots. People like to say roots are not efficient, but they are VERY efficent at moving air. If you are trying to make 20psi of boost then a centrif is the better option due to their efficiency and easy intercooling.
Don't confuse efficiency with flow. Flow makes power. Boost is no good without flow. Efficiency as a compressor a centrif. is better, but only at higher boost levels. Of course there's always alcohol injection if you want to push it.
For the level of performance we are talking the roots blower will get there with ease and have a lot more torque from idle on up. If you are shooting for peak HP then a centrif is a better option. Look up the dyno sheets on a roots blown engine/car. It will be as flat as Kansas, no sharp peaks and it will keep going up until you run out of cam.
As far as the intake mis-match that is something that can be fixed though it's probably a minor issue at best. I know a lot of BBC guys run oval port heads with rectangle intakes.
I'm not trying to sell you on one or the other. I just want you to know the "truth" and not the "perception" about roots blowers. They make big power and torque.
Don't confuse efficiency with flow. Flow makes power. Boost is no good without flow. Efficiency as a compressor a centrif. is better, but only at higher boost levels. Of course there's always alcohol injection if you want to push it.
For the level of performance we are talking the roots blower will get there with ease and have a lot more torque from idle on up. If you are shooting for peak HP then a centrif is a better option. Look up the dyno sheets on a roots blown engine/car. It will be as flat as Kansas, no sharp peaks and it will keep going up until you run out of cam.
As far as the intake mis-match that is something that can be fixed though it's probably a minor issue at best. I know a lot of BBC guys run oval port heads with rectangle intakes.
I'm not trying to sell you on one or the other. I just want you to know the "truth" and not the "perception" about roots blowers. They make big power and torque.
While there is little doubt that port mismatch between oval and rectangular will run, it does not appear an optimum installation.
If you look at a pair of ported heads & intake, there is a lot of effort put into making sure all transitions are smooth - the mismatch in the photo leaves an abrupt jump that has to cost some hp.
Will it work - yes. Is there a better (and more expensive) alternative - yes.
If you look at a pair of ported heads & intake, there is a lot of effort put into making sure all transitions are smooth - the mismatch in the photo leaves an abrupt jump that has to cost some hp.
Will it work - yes. Is there a better (and more expensive) alternative - yes.
The mismatch wouldnt concern me mutch since its being force fed. I would think 600 HP to the ground should be an easy task.
With my stock LS1 heads on my Procharged Camaro it made 570 Rwhp at 10# boost and only 346 cubes. That was with a completely internally stock motor less cam/springs. By changing to a set of worked over LS6 heads it made the same power, only at less boost. It felt more responsive on the low end and my air intake temps dropped but over all it wasnt worth the cost/hassle. I never ran the nitrous on the dyno, it was mainly to help with 60' times at the track on a window switch.
![Image]()
![Image]()
![Image]()
With my stock LS1 heads on my Procharged Camaro it made 570 Rwhp at 10# boost and only 346 cubes. That was with a completely internally stock motor less cam/springs. By changing to a set of worked over LS6 heads it made the same power, only at less boost. It felt more responsive on the low end and my air intake temps dropped but over all it wasnt worth the cost/hassle. I never ran the nitrous on the dyno, it was mainly to help with 60' times at the track on a window switch.
1 - 20 of 21 Posts
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
-
?
