bone stock '78 360. I am wanting to cam it & get out there on the track & be a little competitive (2bbl & 9-1 CR limit). Have a Hughes SEH3636AL-6 hyd cam .546"/.546 lift that I would like to toss in. with how far down the pistons are can I likely get by without checking for interference? I know ideally I absolutely should degree it & check the VP clearance etc but I am under a time crunch. thank you for your time. EDIT The concensus is the 2bbl 360 cam has .410/.410" lift.

I don't see that cam on their web site? One thing to add is that the heads guide and seal area won't support that lift typically.

You know the correct answers, check it out thoroughly ,DUDE
If you don't you know Murphy will stick his boot up your tail, correct

if your running stock pistons you should be fine, they are so far down the block it is pathetic, something like 1/8 inch plus a dish. I also doubt your going to actually get 9 to 1 with them but with some heavy milling and thin head gaskets... maybe but you will still have a lot of clearance because the pistons are so far down.

Maxx that probably clinches it as a no go right there. Cab you are right I know better (just a bit desperate). Dave 9-1 is the class CR limit (not sure why I threw that in) as you are correct, the actual SCR is probably in the low 8's if not the high 7's. Alright I will run it as is (for now), thanks guys.

What about the valve guide to retainer clearance? Are these stock heads too?

Its not the lift, it's the duration. Quick and dirty bring it to TDC overlap. wrap a rag around the rocker arm. Grab the rocker arm with big channel locks and open the valve. How far did it move before it hit? That will get you ballpark.
Doug

Hughes has a family of lobes that it has ground on a camshaft core. SO, even if it isn't in the catalog there's no reason you couldn't get one made to your wishes. Intake lobe, Exhaust lobe, LSA, should be able to be requested. The SEH series is the latest series so it should be pretty easy.

The stock compression height is about 1.576" which leaves you 0.111 down in the hole. There is also a 3" diameter by 0.090" deep dish. So from the deck the lowest part of the piston is 0.201" down.

On a stock 360 you need a minimum of 92.2cc to get 9:1. The piston being down adds 22.9cc. There is another 10.4cc in the dish. So, from piston top to deck is 33.3cc. Minimum head gasket is something like 5.2cc. So all told there is 38.5cc under the head surface. If the head is a stock 73cc you have total 111.5cc, making 7.61:1 compression. 111.5 -92.2 = 19.3cc. That's extra. You cannot mill the head enough to get there.

R.

Hello Dog, I've been wondering where you been. Thank you for the detailed 360 specs that likely could not have been found anywhere else, appreciated!. It is a bone stock 78 360 & my Cornhusker buddy had suggested a cam swap to wake it up a bit so I thought I might toss the Hughes cam I have in there but since it will have retainer area issues I am gonna just swap the truck pan off of it & toss it in there just to get running (& a new timing chain). It might blow up but until then it likely will run long enough to let me evaluate the rest of the car (74 dart/904/7&1/4) out on the track (gonna be interesting to see if the welded spiders 4:10 7&1/4 hold up!). yes I wont even be close to the 9-1 upper limit allowed & it will be a dog anyhow beings it is a high mileage stocker (EQ heads/weiand stealth/eddie performer intakes are allowed) but I just need to get out there.

Advance your cam first thing to get your low
end torque

that's an engle kv1 profile. 269@.020", 239@.050, 155@.200, .364 lobe lift. probably around 280-285 on the seat. i'd worry about retainer to guide issues with iron heads.

that crossed my mind but with it being a high rpm circle track raceing I'm thinking I should leave it be (or even retard it as I have the 3 keyways) but I am for sure open to suggestions.

What RPM do you plan on with your gear

I was thinking 6K + with the 5:57 8&3/4 but with this 7&1/4 I ain't sure but I wanted to try something trick this year but the head gasket from hell situation then the low oil psi has sidetracked me. I'm about ready to pay someone to build me one!.

That would explain why Maxx could not find it on Hughes' site. & I ain't sure I really wanna make a purchase from them again (good tech but too much rudeness).

Stop thinking circle track = high RPM. The crate motors that are winning in everything are not out powering or out RPMing the competition. Work on the chassis. Handling is the key. You need some torque to get that thing off the corner (Advance cam or upgrade slightly). Figure out what you have to do to be the first one back on the gas in the corner and you will be surprised how little motor it really takes. I'm running a smog 360 with a whiplash cam and zero lifter preload and turning about 5400 rpm. That 7 1/4 rearend have c-clips? Don't want to see an axle come out and you end up on you're roof

Along the same thinking with the spring off and a new seal to hold the valve in place goto full lift and then push the valve down that the new seal is holding up and use a fine tip marker or wrap a section of masking tape the measure off that.

I always clay them but if I want to get a general idea early on I do the above.

Many ways to get a ball park figure.

iirc it had C clips. My racing partner Johnny is gonna be driving & he owes me money so for sure I wanna take care of him (at least for the time being) at least till we get even steven. I will grab a rag & check clearance at TDC overlap to get a ballpark. EDIT I have a PM out to Dwayne "fast68plymouth" for a cam recommendation

Axle flange failure (breaking the flange off the shaft) and C-clip failure seem to be the most common failures with the light duty rearends. I'd get that thing upgraded as soon as possible

He's payin me off as fast as he can