What is the difference between the Gen 1 and Gen 2 Thor heads?

Randy

here's the story as i heard it. my new all aluminum block is coming from c&c motorsports carrol told me that art francis ( owner of blue thunder) is having quality control problems with his castings so he went to a small metal forgery out in california. i guess its a quality shop but because its so small and everybody is on to this place now, the foundry doesn't want to loose any business so they are making promises on manufacturing deadlines that they can't keep and they are way behind. my engine builder is good personal friends with art and i actually have an thor intake but couldn't get heads. now from what i understand art has maybe like a handful of the new thor castings at his shop but refuses to set up his tooling to do only a few sets of heads he wants to run off 50 or so at a time understandibly so but IMOA pump out the sets you have and atleast put out a few fires and get some r&d going on these things. i waited long enough since last year i heard about the new heads and got fed up and went to the profiler's. also from what i heard the 2nd gen heads intake ports were raised up another .300 over the originals the exhaust ports were moved over .100 and the rockerstand bolts got relocated out of the intake ports, so there won't be a readily available rocker system for these for quite some time either. but i totally agree these heads will be bad *** and are for larger mountain type motors on a motor like mine i would have to spin that bitch to 10,500 rpms the ports are huge also part of the reason why he made these new heads was to be able to bolt them on out of the box because he is getting tired of all these places getting crazy money to cnc them. i heard 550 cfm's right out of the box on the intake ports and i'm sure the exhaust are around 400.

c.evans
Brian,

I'm finally getting back with you in regards to the questions you asked a while back.



Thor Gen II

1. Roof length = 8.188

2. Floor length = 4.812

3. Average length = 6.500

4. Port floor from deck surface = 2.700

5. Port roof from deck surface = 5.375

6. Centerline = 4.038

7. Runner volume = 470 - 475 cc



2008 Profiler 205

1. Roof length =7.688

2. Floor length = 4.093

3. Average length = 5.600

4. Port floor from deck surface = 2.325

5. Port roof from deck surface = 4.990

6. Centerline = 3.650

7. Runner volume = 420 cc



Hope this helps,

c.evans
Brian,

Just a little more info. The Thor Gen II heads intake port opening at the flange measures 2.675" tall X 2.125" wide with large rounded corners. Probally a 3/4" or 1" radius.

Likewise the Profiler 2008 #205 heads intake port opening at the flange measures 2.650" tall X 1.970" wide, again with large rounded corners. Probally a 3/4" or 1" radius.

Hope this helps,

I'm trying, but I haven't got that far yet. I know they take a longer intake guide than the older first generation heads did. I had a blank (length), 2.500" intake valve come in today for R&D purposes. I already had several 2.450" R&D valves. The suggested valve diameters are 2.500" and 1.850". We'll be looking at a 2.200" and/or 2.300" installed heights.

I'm going to look long and hard at 1.840"-1.850" on the exhausts. Lem and I like the smaller exhaust valves. Reason being is that I've had several used C-460 and Profiler heads roll through here for freshen-up valve jobs. Those with the bigger 1.900" exhaust valves always tend to have some seat distortion from the heat, right where the exhaust valve seat intersects the intake valve seat. Things get awfully close there and often produce a razor sharp edge that we need to take care of.

Back to the Gen II Thor heads, the intake guides and exhaust guides are different, and that's a good thing. Additionally they have the good CuBe seats which I think I've already mentioned. Also they are supposed to take a different shaft rocker arm set-up than the first generation, if I have my info correct. We'll be looking into that too.

Hope this helps,
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Charlie Evans