Don Terrill’s Speed-Talk

Just looking for some info on rough HP numbers with mild to wild upgrades. Building one for turbo use and trying to calculate some power numbers. I am just finishing the head and it's flows pretty well and looking to run a comp cam and offy c series open intake with lots of boost.

We built one a few months ago. Go here and watch it run. We called it Frankinsix. http://www.youtube.com/watch?v=XMPnlEWW43w
We used a lot of different parts. Sorry the lead in for the video is long but I was on a roll.
BTW we got 311 hp and 375 TQ. N/A.

Donny

I don't remember hearing any power numbers, but one of the wilder modifications I saw years ago was to section a pair of Boss 302/351 Cleveland heads to fit on the 300 block. I think maybe the late Kay Sissell pioneered this(?). The one example I saw at the track had a very large amount of silicone visible at the joint, but I bet it would be a much easier thing to do today, with the aluminum heads that are out there.

Mark
I've made pistons for a drag race team that's used every type of cylinder head imaginable, since the '70s. if you're really interested in talking to them I will see if its OK to give you their phone #. they also lurk on Speed Talk so they may see this.
Dave

One of my favorite engines from back in the day. On limited dirt tracks, it would hold its' own with 302" SBFs and SBCs.

Sounds like you are doing a mild street build. With the OEM iron head, they respond pretty much like any other of a similar bore and stroke. The inline config makes the turbo plumbing much easier than V-type engines.

Assume you have milled the head and block and installed good hard exhaust seats and stainless valves. That is the one weak area when using lots of turbo. Also, consider a crank-triggered ignition.

This recollection goes back to the dawn of time, but IIRC, to help the head and gasket hold the boost, we tapped the head bolt holes with a bottoming tap. Then, we spot-faced the bolt head area of the head to take a hardened washer. Stacking everything up, we measured washer, head, gasket and hole depth. We got corresponding length head bolts from ARP. (NO, you don't want head studs on an inline six. The one guy who tried it, took a cherry picker hoist and three guys with pry bars to remove the head.) This also reminds me, main studs and a line hone are a must for serious boost.

Just for shitz-n-giggles, search out some of the old Hot Rod Magazine Engines Annuals from the late '60s/early '70s. Ak Miller was building some of these for Ford. I remember detailed stories on several.

jack vines

With stock or a tad better flowing heads you should have no problems with 8 psi of boost in regards to the block or the main caps.
These heads are basicly 351M castings and I recall doing a few porting jobs some years ago for two V8s, and with stock V8 valve sizes I had them topping 270 cfm@28" up from the stock 210 or so CFM. and I recall getting 195cfm on the exhaust side, both at 650" lift.

Hp numbers you could make with 250 to 270 cfm of intake flow may create a need to make up a main web/ main cap support and a custom pan to keep things in one piece.
The heads do have room for a bigger exh valve which is a good thing to put in place while you in the process of a re=build.

Thanks guys i just finished the head which has 1.94-1.60 valves which appears will flow 220-170ish will know in a few days when i get time to flow it, i will run the comp 218-218 .456-.456 cam, offy c series open intake and probably my modded 650 holley for blowthrough. It will be intercooled with alky injection and race fuel with higher boost. I found a guy running 10.90 @ 120mph in a 3028lb maverick with an all stock 300 with 25psi. I'm hoping to make 250 NA then 500hp with 15psi, does 250 NA seem realistic?

Here's a couple of links to some lengthy threads about vintage 300 builds.

http://fordsix.com/forum/viewtopic.php?f=2&t=56091

http://fordsix.com/forum/viewtopic.php?f=2&t=59323

Yes, 250 NA would be cake, IF you were using some compression and headers. However, with turbo compression and header, it is just possible.

jack vines

Mark,

I built an 11.5:1 CR, 321 GMC with a modified stock head for our HAMB dragster and made 347 HP @ 5600 NA. You should be able to make 1 HP/cubic inch NA pretty easy. I'm sure the 292 is a much better..... read that as cheaper..... engine to build than the GMC. I think you'll see 500 HP or better @ 15 lbs of boost.

Ron

I would play around with the valve job to get the best .300 - .500 flow you can. You'll need it for low boost and a moderate cam to come close to your power goals.

Well i flowed my head today and it's better than expected for stock stuff. I just used a stock newer 1.94 LT1 valve and a decent 1.60 exhaust valve with no pipe. I'm really hoping this engine will make 250-300HP NA which seems very realistic with this head.
Intake Exhaust
.100 73.7 46.4
.200 143.3 92.8
.300 192.4 132.8
.400 231.0 159.1
.450 236.5 167.9
.500 241.4 173.7
.550 245.2 178.1
.600 245.5 183.9

Not bad at all. I would say the next trick will be induction. Although at that power level your intake should work fine. With that cam I think you'll be around 260hp NA, with 15 psi I'd guess about 400hp, which is really pretty solid considering the low rpm you'll be making that at.

just something to think about - remember, that head flow has to support a larger cylinder than an equivalent V8...

50 CID per cylinder, which is the equivalent of a 400 CID v8.

all the best, I for one will be following with interest

I ran the numbers on wallace and the cross sections good for 5500 rpm so that's perfect for this setup. If it makes 260 NA it better make more than 400hp with 15psi, it should make 520 in perfect conditions. Most of my setups seem to double the NA power with 16psi with intercooler and meth injection for cooling.