I am wanting to put a thumpr cam in my 400 and I was wondering if it is a hydraulic roller or flat tappet pre thumpr. And what all I would need to put the cam in.

 

They come either way.

1980 FORD 6.6L/400 COMP Cams Parts and Accessories - SummitRacing.com

 

Those cams sound good. That's about the only good I have to say about them. They have lazy lobes and do not make the best power.

Comp XE series cams is where it's at.

To me the risk of flat tappets is just too much anymore, I'm going roller

 

Hi 400inatruck,

I'll assume that you've done your homework and chosen those cams based on your desired driving characteristics.

There are benefits to fitting the roller cam, but you have to decide if the extra cost over hydraulic cams is warranted.

Running flat tappet cams is no problem as long as you follow the break in instructions to the T, and thereafter use oil with an API of 'SG'. I.E. oil with a zinc ppm of +/-1200 and phosphorous ppm of +/-1000.

Once you've singled out a cam that you like, check the manufacturer's suggested valve train specs and timing chain kit.
You don't want to find out that you have valve bounce coz you didn't check your existing springs and it turns out that their pressures are too low for example.

You also need to check the cam timing and match it up to your existing/desired Compression ratios and cranking pressure.

You wanna also know that you're going to have sufficient valve to piston head clearance.

I'd also fit a new oil pump and ARP oil pump drive shaft, and get a new set of oil pan gaskets for when you take the oil pan off, which you'll need to do.

Checking that the dizzy drive gear is spot on wouldn't hurt either.

I hope that's what you meant by ''what all I would need to put the cam in''.

 

What valvetrain pieces would I have to change if I chose to switch from a hydraulic flat tappet to a hydraulic roller? The rebuild is a lil over a year. I haven't had problems with it, just want a different sound at idle.

 

Generally, any switch from the roundish stocker requires new springs. With the roller, it's going to be pushrods as well. You will want to make sure the rocker set up is 100% as well, as wear there will cause you grief.

You must avoid valve float. Your motor probably has never seen the north side of what, 3500 rpm, maybe 4000? The cams you are looking at run up to 5000+. You absolutely CAN NOT have coil bind, which can happen with a higher lift cam and stock springs. No cheaping out on the valve train. The cam provider will also have springs etc, and probably pushrods to boot.

 

Go to comp cams website, pick a cam, then click on the cam card details for that cam.
It will show a list of suggested parts. Note the valve springs part number, then look at the specs of those. E.G. Seated height and seated pressure.

These can then be compared to what you have. If you don't know your current valve train specs I'd be inclined to find out.

That said, if your engine is only a year old without problems, and all you want to do is change the exhaust note, I wouldn't touch the cam, but rather consider modifying the exhaust.

 

Ok. Thanks y'all. Sorry I haven't been on here in a while. I've been busy with my truck in my autobody class at trade school.