Can a LT1 block with a .030 bore Accommodate a 2.10 intake valve on a 23degree head?

 

I think it's technically possible (The cylinder is wide enough anyway) but I don't know about a 23 degree head. If you had something like a 0 degree head then it would be easy, but a 12-15 degree might be doable.

Just speculation though. I do know that ETP makes a head for the LSx motors that is designed for a 4.0" bore with a 2.1" intake valve, I believe it is 11 degrees though.

 

Yes, that's right about 52% of the bore diameter. Remember big valves need to be teamed up with the right port shape. Something like a LS7 has a big valve for it's venturi because it directs flow to a certain part of the bore and the big valve helps promote that. A 23° head may or may not like that as well, just depends on the philosophy of the head porter and where they are trying to direct the flow into the cylinder. I've seen large valve and small valve 23° heads work well.

FWIW A LS7 has a 53% int valve / bore ratio

Bret

 

Well i ask because talking with a local shop they think using the brodix track 1x heads and converting them would be a good choice to achieve Decent numbers & track times with the 396 im building. Im about 3 months away from purchasing the top end for this thing and im checking every source and recommendation that i get.

http://www.brodix.com/heads/track1.html

 

Well only Brodix can weld that stuff they call aluminum easily.

There are other options out there as well including Dart, TFS and AFR. I'm partial to Dart because I know what they can do if they are done properly.

What is your goal with the motor?

Bret

 

Mid to low 10's on motor.. Full suspension, 28'' tire, 4.56 gears, full weight 6 speed.

Havent looked into dart for heads but would consider them as well. What heads would you recommend I check out?

 

That's a pretty stout goal, should be a fairly awesome car when you're done.

I think the new Dart 15 degree SBC heads flow something like 392cfm @ .700 lift on the intake side. Those are the factory claimed numbers but it's still pretty impressive. You might want to try them.

 

Huh 15 degree heads.. What would have to change to run those on a SBC?

 

What bore? That is a big valve and there may not be much gain (or even a loss) over a smaller, more easily installed valve. When the valve gets too big for the bore there can be significant shrouding that interferes with flow. Unless it is a big bore motor I wouldn't bother.

Oops - you said 30 over. I wouldn't do it. I wouldn't try to go bigger than 2.055". As far as how feasible that is, I'd ask a head guy or someone like Bret who builds a lot of the these things. BTW, here are some area for different diameters and the diameter as % of bore size for a 4.030" bore.

1.94" 2.92 sq.in 48%
2.00" 3.14 sq.in 49.6%
2.020" 3.20 sq.in 50.1%
2.055" 3.32 sq.in 51%
2.080" 3.40 sq.in 51.6%

There are ideas on what is beyond optimum that I am not knowledgable to discuss except that 51.6% is probably too big for a 23 deg SBC head. Also, to get a real advantage out of a larger valve, you need more lift. Another way of saying the same thing, if you think about it

Rich

 

A lot, it's probably not worth it to you, but it would make it significantly easier to obtain those goals making 700hp N/A.

You need offset lifters, rockers, and different pushrods. You also need new pistons and a new intake.

Dart also makes some good 23 degree stuff, I've heard a lot of good things about the Pro 1 heads.

 

its a 4.030 Bore

The Valvetrain on the engine will be fully addressed with quality parts I don't want to scimp on anything and have to do this job over again in a couple of months once this engine is built its gonna have to last until i finish other projects for the wife.

The valvetrain i planned to use would be jesel shaft mounted rockers, Morel link bar lifters,Chrome moly pushrods, Lightweight retianers & Locks & a very good valve spring.

The pistons i would like to keep but if it's something as small as changing the pistons to achieve my goal then i will.

Im currently looking into have a Single plane intake converted for EFI and to work with LT1 heads. Actually Bret is my first canidate to convert the intake for me but i havent got a price for that yet.

Im going to look into darts products now, I was waiting to hear back on the total price for the shop for the heads and conversion work but havent heard anything yet so i might just move on a look for someone else do them for me.

 

Read what I said about valve sizes.

Rich

 

I checked it out, Thanks for the input. I believe the smallest valve i've seen in a head big enough to support a 396 is 2.08 so maybe i'll stick with that size. Im just looking to find the best possible way to achieve my goal.

 

Checked out the Dart Website Looked at there Pro1 Line up the 215cc,227cc, or the 230cc http://www.dartheads.com/sbchpro1.aspx All looks pretty good on there site which ones should i consider out of the pack?

 

I would think for that size motor a 215cc head would be the smallest you could use, but I guess that depends more on how high you want to spin it. If you were planning on using an "out of the box" head with no work then you should probably get the CNC'd 227cc.

Then again, I would bet the CNC'd head was designed for a bigger bore than you have, so it might be a better idea to get the 215cc or 230cc and have someone work them over for you with your bore size in mind.

Just my $.02