Flow data and other ? about 862 heads
09-01-2017, 02:52 PM
#1
Flow data and other ? about 862 heads
I'm gearing up to do a head cam swap on my 2000 gmc 5.3 ecsb. Will have all supporting mods like lt headers, 4.10 gears, e fans , tbss intake, dyno tune and stall. I wanted to use a set of ported 862 heads. And also mill them to bump compression up a full point to 10.5:1 . I see most cnc ported 862 heads flow over 300 cfm. Almost all companies are using a 2.00 intake valve. Except wcch that use a 1.95 intake valve and I can't find flow numbers for them.
What I'm wondering is wont the 2" intake valve cause shrouding/Flow issues on a stock bore 5.3? Is there any one hand porting these heads and getting as good of numbers as cnc ported? I would imagine the 1.89 stock valve is the choke point.
What I'm wondering is wont the 2" intake valve cause shrouding/Flow issues on a stock bore 5.3? Is there any one hand porting these heads and getting as good of numbers as cnc ported? I would imagine the 1.89 stock valve is the choke point.
09-01-2017, 07:59 PM
#2
I'm gearing up to do a head cam swap on my 2000 gmc 5.3 ecsb. Will have all supporting mods like lt headers, 4.10 gears, e fans , tbss intake, dyno tune and stall. I wanted to use a set of ported 862 heads. And also mill them to bump compression up a full point to 10.5:1 . I see most cnc ported 862 heads flow over 300 cfm. Almost all companies are using a 2.00 intake valve. Except wcch that use a 1.95 intake valve and I can't find flow numbers for them.
What I'm wondering is wont the 2" intake valve cause shrouding/Flow issues on a stock bore 5.3? Is there any one hand porting these heads and getting as good of numbers as cnc ported? I would imagine the 1.89 stock valve is the choke point.
What I'm wondering is wont the 2" intake valve cause shrouding/Flow issues on a stock bore 5.3? Is there any one hand porting these heads and getting as good of numbers as cnc ported? I would imagine the 1.89 stock valve is the choke point.
The intake valves do shroud a little when you go to a 2 inch valve on a small bore or at least they show that on the flow bench. However GM produced the L33 H.O. 5.3L and the Later Gen4 4.8L / 5.3L with the 799/243 heads.
Tony Mamo looked into this as well when he designing his new heads for a small bore package last year and went the same route with a 1.95 intake valve. He is flowing right at 300 cfm with a 1.95 intake valve on an AFR casting.
I am not sure you can mill enough to get the compression up that high on a standard 4.8/5.3L. You can put a flat top 4.8L piston in a 5.3L with those heads and achieve a 10.5:1 compression.
09-01-2017, 08:14 PM
#3
I had just found the flow numbers for the WCCH heads when u posted. Not impressed with the flow numbers for the price and options offered..
The compression calculator shows 10.38:1 compression with 57cc heads and my stock short block. Looking at a TSP 224/228 cam.
The compression calculator shows 10.38:1 compression with 57cc heads and my stock short block. Looking at a TSP 224/228 cam.
09-01-2017, 08:32 PM
#4
I wanted to try Either some Advanced Induction heads or TEA heads at some point but I am Tapped out.
I wonder if Frankenstein has any thing for these heads??? May be another source to look into
I wonder if Frankenstein has any thing for these heads??? May be another source to look into
Last edited by 1FastBrick; 09-01-2017 at 08:38 PM.
09-02-2017, 06:23 PM
#6
The tfs205 flows pretty good for an a very small runner with cnc chamber. 2.0 valve. 285 and 228 on a 3.800 bore. 58cc chamber
The step up 215 outflows mamos 220 head also. flowed on a 3.90 bore just like mamo posted. 2.04 valve tho.
So far trick flow still wins in my book.
We have killer pricing also on the tfs stuff we sell alot of the as cast 220s.
The step up 215 outflows mamos 220 head also. flowed on a 3.90 bore just like mamo posted. 2.04 valve tho.
So far trick flow still wins in my book.
We have killer pricing also on the tfs stuff we sell alot of the as cast 220s.
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09-02-2017, 08:50 PM
#8
who hoggs out heads with a cnc machine? Quite a fe places gain flow and keep velocity etc through port design and factor in CSA.
Local hand porters are usually the greedy ones.
Why spend 2k+ on heads for a small bore? Really the most power youll get on a budget is going to ls1 bore then putting money into heads. You can still use small bore heads but have way better flow and possibly see a bump in tq as well.
Of course we cant all do that considering down time, and finding a good machine shop of course.
You dont always have to go forged with a short block build to make power.
Local hand porters are usually the greedy ones.
Why spend 2k+ on heads for a small bore? Really the most power youll get on a budget is going to ls1 bore then putting money into heads. You can still use small bore heads but have way better flow and possibly see a bump in tq as well.
Of course we cant all do that considering down time, and finding a good machine shop of course.
You dont always have to go forged with a short block build to make power.
09-02-2017, 10:10 PM
#9
who hoggs out heads with a cnc machine? Quite a fe places gain flow and keep velocity etc through port design and factor in CSA.
Local hand porters are usually the greedy ones.
Why spend 2k+ on heads for a small bore? Really the most power youll get on a budget is going to ls1 bore then putting money into heads. You can still use small bore heads but have way better flow and possibly see a bump in tq as well.
Of course we cant all do that considering down time, and finding a good machine shop of course.
You dont always have to go forged with a short block build to make power.
Local hand porters are usually the greedy ones.
Why spend 2k+ on heads for a small bore? Really the most power youll get on a budget is going to ls1 bore then putting money into heads. You can still use small bore heads but have way better flow and possibly see a bump in tq as well.
Of course we cant all do that considering down time, and finding a good machine shop of course.
You dont always have to go forged with a short block build to make power.