[BruceWilkie]

Whule doing my spy research for my Ford project I came across this. This seems applicable to our Pontiacs so I thought I would share.

Quote: "Adding a stroker kit new info

Some have asked about a horsepower chart for stroker kits. Some of the most common are:

4.39 bore x 4.15 stroke = 502 cubic inches

4.39 bore x 4.3 stroke = 520 cubic inches

4.39 bore x 4.5 stroke = 545 cubic inches

By adding a stroker crankshaft, the following occurs:

1) For every 50 cubic inches added, the rpm at which torque and horsepower peak at will drop about 600 rpm. So, if your 460 horsepower peaks at 6000 rpm, a 545 will peak at 5000 rpm. This assumes not changing anything else in the engine combo.

2) If you wish to maintain the same horsepower and torque peaks when you increase the stroke, you need to add between 12 to 16 degrees of additional intake duration for every 50 cubic inches added in displacement. Respectively, exhaust will have to be increased also.

3) The amount of torque below the torque peak, and at peak, will increase. This is a good thing, especially for street cars.

4) The larger the engine, the faster it will pull rpm. The weight of the rotating assembly is almost the same on all strokes, from a 460 to the 545 assembly, but as you increase the stroke, the engine now has more displacement pushing that assembly.

5) If you keep the same cylinder heads on the larger motor, you need to add overlap by using a tighter lobe separation, usually 1 to 2 degrees for every additional 50 cubic inches, until you get to 270 degrees @ .050" lift. Above 270 @ .050" duration, you need to bring lobe separation wider to limit overlap that is inherent after that duration. BSFC numbers go up needlessly with too much overlap.

The tighter lobe separation angle adds the necessary overlap to feed the additional inches, however, it does close the intake valve earlier. The horsepower peak numbers will be similar, but will occur at a slightly lower rpm with the tighter LSA. It is usually good not to advance the cam as much as usual.

If your compression ratio is "on the edge" running on pump gas, it may be inapproopriate to tighten the LSA because it increases lower rpm cylinder pressures. The tight LSA adds low and mid range torque because of the lower end cylinder pressures, but may not be needed if the vehicle combo is traction limited. As an example, a street vechicle only running on street tires.

6) Peak horsepower will increase slightly."



http://460ford.com/viewtopic.php?t=23787 Is the source.

The topic is basic build recipes for 460's. SOME are applicable/similar to basic 400 combos just adjust for the stroke increase if doing a 428 or 455. Note the iron heads have better flowing intake than our Pontiacs but the exhaust holds the Ford back. Current aftermarket Ford heads are way ahead of us in development. That said an IA2 with CV1 HP's or tigers can compete well in the 500- 550 cid range if properly executed. (Particularly if the Ford is using a prduction block vs the big bore race block) Be sure you know what your racing against if your betting $$$.

One other thing I learned Kaase has tested a ported Alum SCJ head(he helped design) his P51 cylinder head, and his new "Boss 429" head on the same 521 motor . All 3 heads flow into the low 400's and have similar low lift numbers. Using the same cam and compression and carb the power numbers are close to 100 hp greater EACH STEP up in head design. 700/800/900 hp respectively. Compression was approx 10.7 all 3. Same cam mid 250/low 260 108cl 740/750 approx. lift. Perfect example of flow quality / chamber design vs flow quanity. These are "street" heads NOT race only! Race heads are 100+ cfm bigger and intended for those 4.5"+ bore race blocks.

When I get back to my Pontiac project I have some ideas to explore for sure. Its good to touch base with the competition.

[Ron H]

Great info Bruce. Do you know the differences in Port Volumes for each of the Kaase heads tested?

[BruceWilkie]

http://460ford.com/viewtopic.php?t=18321 here is tons of BBF head info
I'll have to search thru Kaase's posts for port volume info on his heads. From what I've read so far the boss "street head" is similar low and highlift numbers to Ported SCJ and as cast P51 with slightly better mid lift flows. All 3 are considered "street" heads. "Race" heads are 500 + cfm 400+cc. Kaase says the biggest difference in power is the fuel distribution thru the port and into the chamber, between the 3 street heads mentioned. flow quality vs quanity.

The site is an excellent source of "enemy" info! I've gone from who cares about Fords to hmmm I think I am going to like this. Still love my Pontiacs but I dont mind adopting one of these for sure.

[Mr. P-Body]

The BBF is a MONSTER when properly built. As said, the exhaust side is in serious need of help. Mr. Kaase is one of the "gurus", but as he markets his own design, another head out there for the Ford gets overlooked by some. "Blue Thunder" is among the better ones. P-51 has been a bit of a let-down due to all the hype before it was released. Blue thunder uses those awesome CJ-type intake runners, but also uses a a straight "copy" of the BBChevy exhaust port from the good rectangular port heads and uses BBC headers as well. Anyone familiar with BBC knows, the exhaust port is a little "too good" for the intake. This makes the Ford head incredible. IMO, the best "streetable" head for BBF. Hard to argue with the "Shotgun" (Boss) heads for a high-end race engine.

FWIW, we built a 514 Ford here, using "D0VE" heads (that's a "zero", not an "oh"), with minimal intake porting, but "filled" the floor in the exhaust, effectively reducing the cross-section by about 35%. By reshaping it, we doubled the flow from 110 to 220 @ .600" lift. The thing is a BEAST. It makes right at 800 HP, 12.5:1, 270 @ .050, .650" lift. Revs to 7,200.

Like the slogan on our website says: "We don't care WHAT color you paint it, we'll build it!" We like Fords here just fine. But Pontiac Metalic Blue is MUCH prettier than Ford Blue...(:-

Jim

[PunchT37]

Originally Posted by Mr. P-Body

FWIW, we built a 514 Ford here, using "D0VE" heads (that's a "zero", not an "oh"), with minimal intake porting, but "filled" the floor in the exhaust, effectively reducing the cross-section by about 35%. By reshaping it, we doubled the flow from 110 to 220 @ .600" lift. The thing is a BEAST. It makes right at 800 HP, 12.5:1, 270 @ .050, .650" lift. Revs to 7,200.



Jim

7200. And that`s with those huge rod journals.

[BruceWilkie]

Most the Ford strokers are available in the BBC rod journal size like our stroker kits. Some kits stay with the 2.5" Ford rod journal. Mains are 3 inch.

Jim absolutely agree on the color. The Blue thunder is a great head the Chevy exhaust port option makes it even harder to fit headers in a 70 Torino or Mustang. I'm debating both options. I've heard that the BT's are of excellent quality and use threadserts vs helicoils in all the bolt holes. One Shop I spoke with said depending who does the valve job and porting not much difference between BT's P51's or TFS SS heads.(with Ford exhaust port) He said the BBC ex port will be a lot of mods to my shock towers to properly build a header but a minimum of 20 hp to be gained by using it. Mid 10 compression properly ported and cammed 800 hp is quite doable. Suggested race block if I wanted to go the high compression 1000 hp race gas path. Std 2 bolt caps with studs and block fill can also handle 800 hp if revs are kept under 7k. But (like our Pontiacs) 4 bolt caps are highly suggested to control cap walk. Roller cam Fords need oil restricted to the top end.

If this doesnt sound like similar issues we deal with I dont know what does. Kaase likes Pontiacs intake runner placement, when using a Victor single 4 on the Ford it has 4 runners too short for what he would like to have.(ours is better because the runners are longer on the center 4 cylinders). (In dual 4 tunnel ram applications its no different)

I think if anyone really were to aggressively persue buiding a RA5 head and apply some of the design of the BT's or P51's, the head could be absolutely perfect for a big cube IA2 Pontiac. I hope we dont have to have a Ford guy do it for us.(Like the Indy Mopar guys built a hemi head for the Ford boys.) The CV1 is a step in that direction but a revised RA5 would likely be better and at least of Pontiac history. If Pontiac had kept it where would it be revised to today?

I looked over a set of Edelbrock Victor heads for the BBFord this weekend at the Goodguys show. For the money they arent much of an improvement over the stockers. They did basically a stock head in aluminum with a 320 cc intake port and exhaust port change similar to what You did with an Iron head Jim. I could see rough casting groove where the seats meet the chamber floor too. not impressive qc to me.

For you guys stepping up to a big cube IA2 there is alot to learn from these Fords that we can use.

[Thumpin455_GTO]

Interesting.. a Ford thread. I feel your pain with the header issues on a 70, I have a 71 I need to do something with. Right now I have a 351C 4V for it, but the LIMA has me interested as well. Not sure what direction to go with it at this point, so it sits waiting to get worked on.

There are two Fords taking up the shop where I should be rebuilding GTOs, Birds, and T37s, and both have engines painted Pontiac blue, because it is a much nicer color. All engines I build get painted that color now. Even my brothers 68 Mustang is Pontiac engine blue.

Where would the RAV be now if it were revised? Look at an LS1/LS2 and the answer will present itself. A Pontiac symmetrical port head would be just the ticket for forced induction, alleviating the hot spots between the center exhausts. Make the ports flow rather than huge and the RAV would make the Indian a 'contenda' again...

not that I could afford them..

Ford and Pontiac are more similar than dissimilar, particularly when you compare FE and Lima to Pontiac, then compare it to the orange engines.

[Tom Vaught]

Quote:

"Most the Ford strokers are available in the BBC rod journal size like our stroker kits. Some kits stay with the 2.5" Ford rod journal. Mains are 3 inch."

I worked with a guy a few years ago who was a Top Altered racer. BB Chebby guy but he would have his cranks ground for the Ford 2.5" rods and normal BB Chebby mains. Used custom rods so the 2.5" big end was not an issue for him. When he eventually hurt a bearing, (and you will hurt something if you are fast), he would be able to have the crank cut for the 2.20 rod journal size and keep racing with a perfectly good crankshaft. SMART!

Tom V.

[455Grandville]

Couple Ford projects Im building :

442 cid FE Ford : 390 block bored to 4.130", offset ground 428 crank (3.98" to 4.125")
240 Ford six cylinder rods, pop up pistons 12.5: 1 comp to run on E85. Should be a torquey bastard for the 85 Ford F250 4wd.

427 based 351W : bored 1/8th inch 4" stroker crank. 351W's can take 650-700 hp before the mains move & pull apart. I welded a skirt/brace making it a girdle, it's going in a buddies pulling tractor and we're shooting for 850 + hp on a budget.

Pbody: You're correct about the 460. Before gas got so high I built a 514 shortblock for a F350 just for pulling a trailer.