best valve size 1745cc combo

[Aussie Rob]

Playing around with some parts left over from the last 15 years. I have a good 1300 case looking at building a76x85.5 1745cc engine.
Heads are new 043s with reworked chambers and heavily ported  with a little welding. Standard 14mm plugs. My aim is either fit 40x35.5 or 42x37.5 valves. Compression will be 9.4:1  43cc chambers and a zero deck using 0.06 copper head gaskets. Duel idf44 carbs will be used and a 1 5/8 merged exhaust.
 Cam is a CB Ghost Rider cam giving 256*@0.462 lift with 1.1 rockers. Could use a K8 i have with 1.4 to get more lift/flow from those ported head. Gas is 98ron premium unleaded.
 What i really want to know is the best workable combination between the valve sizes and choice of cams. Which combo would work together to best  maximize horse power and drivability. This will be a weekender.

[Ohio Tom (DdK)]

I would stick with the 40 x 35.5 valve heads. The valve size won't be the limiter.
Even if you ported them to the max, you won't be limited by valve size.
I have a set of 40 x 35.5's that are welded up and ported to the max. They pull past 8,500rpm on my 2054cc motor.

[Aussie Rob]

Hey! thanks Tom Can always count on your good advice. So going for the 40x35.5 valves should i stick to the CB ghost rider cam as a good combo or k8?  These heads wont be too big for the combo i hope.

[Ohio Tom (DdK)]

The K-8 will open un-leash all the power that your heads can provide.
However, you will give up somthing (more like alot) of bottom end and midrange.
K-8 won't "kick" until around 4,000rpm with your small-ish displacement.

It all depends on what your priorities are.
Dependable, high milage street motor, stick with ghostrider.
Max performance small motor that's just barely street-able.. K-8.

I vote K-8.
Some years ago, I blew up my main motor mid-race season.
I threw together a 1755cc (69 x 90) motor with some good flowing, small valve heads, 44idf's and W-125 cam (similar to K-8). All parts I had laying round or donated by CLF folks.
It was a total dogg driving around, but I loved it.
Revv the snot out of it and she'd run low14's in the 1/4mi in my superbeetle.
powerband was 4,000-7,600rpm.
 

[Aussie Rob]

Looks like my mind is made up. I have the 2276 AJ turbo engine in the pipe line as well. I thought i would put that big one to the side and build my NA motor . I just LOVE the induction roar from a set of webers at full noise!!

[milo]

After experiencing a fee of the FK40 series cams I just built a 1776 daily driver (On the aggressive side). I used a FK44 because it gives you the bottom end of engle 110 and the top end of a engle 120 (Well more actually).  I set it up at 9:1 and relatively tight deck but only has stock valve aggressively ported heads.  With 44 IDF's and 1 3/8 exhaust (Daily Driver, Stock Valve) I have let a few people drive it any everybody agrees it makes a 1776 feel like a lot more. It might be a good have your cake and eat it to cam for you.  With the 40 series it's best to have the lifter bores sleeved but that is realivily inexpensive considering the power/drivability gain.  Brother Machine did mine and they were fast and did beautiful work, I highly recommend them. 

Hope that helps,
Nate

[Aussie Rob]

Thanks for the tip Nate. I have the duration specs of the fk44 as 256* the same as my off road ghost rider. The only difference being the fk is designed for ratio rockers  while the ghost rider is a 1:1 ratio rocker cam. It too has aggresive ramps very similar to a vz25 cam......It sure is a tough choice given all the variables and good advice. I do wish to use what i have at home however. I have 4 cams at the moment just begging to be thrashed. I can only choose one however.
 So far the nod is going to the k8 considering it gives 0.534 lift which my heavily ported heads will flow easily....
 

[Sam]

IF your slightly leary of the K8 due to higher rpm powerband. you could call steve long racing and get an XR302 on 106 degree lobe centers.  Mine starts pulling at 2500 and is pilled at 8000. It doesnt pull down low like a vz25, but it does produce alot more torque than a fk8.