Head advice for blown BBC in a FED

Hey everyone, been doing a bit of reading and research on here now that I've got my FED home and am looking forward to learning from the experienced pros here. It's a 180" and I'm building a 496 BBC with an 8-71 and injection (110 pump) for it. The short block will be 11:1 with conventional heads (119cc chambers), and I'm only planning on running about 15% over on the blower as this car is really light and I'm not out there to break any records (no faster than 7.50). This is a car I'm building to pay tribute to the past and have some fun.

I've been trying to figure out what intake runner size would be best to go with for this combination. I figure the motor wouldn't be making more than 1000hp with the amount of boost I'll be running, but wouldn't mind the heads to be able to work with 1200hp if I decided get some more out of it. I've been looking at the Brodix BB 2X heads and the AFR Magnums (fully CNC'd), and am not sure whether I can get away with a 340-345cc intake runner or should I be looking at 360 and up? AFR has a nice set of 377 heads but I'm not sure if that's going to be too much for this motor. I'm not looking to spend a ton of money on heads, but if I should be going with a higher cc for the intake, then I'll get what I need to get. Tranny will be a PG if that helps.

Let me know if there are other details that I've missed. Thanks for the help!

J.C.

 

bbc heads

we ran a set of AFR 345's on a BBC making that sort of HP and they were great. You are spoilt for choice as almost any average rectangular port head would work fine with your combo, it will probably boil down to best value for money

 

Check your PM's

 

Agreed that most BBC heads would work. We have done several low boost engines using the Brodix BB3 with good results.

 

Thanks for the advice everyone. I wanted to make sure that I wouldn't be making any sacrifices by choosing a head that is less than 360cc. This will help out on the budget as well.

On another note, when buying assembled heads, is it common to end up replacing the springs that come with them because they won't have enough seat pressure for blown applications? From reading on here, it seems that everyone is suggesting spring pressures over 300lbs which I would think are higher than what comes with most heads in the category I'm looking at. Also I'm sure the chances that the included springs will match up with the cam I'll end up with are pretty slim.

J.C.

 

BB3 with the big spring is 315# on the seat.

 

I went and checked the specs after I read our post and those heads seem like a really good bang for the buck, especially with the larger spring option and 2 degree rolled valves. I'll keep these as a first choice and compare others to them and pricing.

Thanks again for the help! I'm sure you'll see more of me as the build goes on!

J.C.

 

For what it is worth, I run BB2X on 496 and 540 BBC with 14-71 at 45% over in tractor pull competition and they worked very good. We had some worked BB1's on a RED (496 with 8-71) and got good numbers. We ran BB2X this past year on our twin turboed 540 and I was satisfied with their performance but are changing next season to a big chief/duke style. No hemis here. JW

 

BBC heads

J.C.

We have had Very good luck running used Dart 360 heads on our 496 BBC, we run our dragster at 6.00 at 232 MPH and it works out to be about 2400 hp, a used set of Dart 360 heads complete are very reasonble, and if you treat them good they hold up very well over the years,


Also ours do not have any fancy port work, and they flow about what dart sells them as 360 CFM, with our bore and cam profile. for the price you can't go wrong. IMO

just my 2 cents

Butch

 

It great to hear of some real world examples.

With the BB 2 Xtra, there's a set that has 365cc intakes runners and the bigger 1.645 springs, but the seat pressure is only 250lbs. Would that be alright for the boost pressures I'm planning on, or would the springs need to be replaced?

J.C.

 

Keep an eye on installed height also, you don't mention what lift your cam is.

Corey

 

No cam yet, wanted to decide on heads first, then choose a cam to work with them. Lots of grinds out there, so shouldn't be an issue finding one to work with the heads. I will keep the installed height in mind though. Going to give Crower a call to see what will work best and give them the specs of the heads I decide on to see what will work.

J.C.

 

The reason I mention it is obviously coil bind. If you can set up your heads for a 2.100" installed height then you have a way bigger selection of cams. You are good to .900" lift with that arrangement.

Corey

 

Makes sense, thanks for the heads up. Looks like the BB-3s I'm looking at have the 2.10" height, so that will work out well. Is there much of a difference between 2.05" and 2.10" in terms of lift and cam selection?

 

The 2.050" your limited to about .800" lift, the 2.100" is .900" lift. I use the Nextek springs 2.100" installed and that gives you 350lbs/seat.


Corey

 

Right on, thanks again!

Now I just have to get a couple more paychecks in the bank and I can start making some orders!

J.C.

 

IMO for the power your looking for, the reliability and the type of heads you are talking about, there is no reason to lift the valve over .750-.800".

 

I agree. I don't think there will be a need to go over .800" with the cam. But I don't think it would hurt to choose a set of heads with springs that could handle more if I decide to do something different down the road.

J.C.

 

Ding

Corey