There have been discussions about combinations that have heads which are "too big". What about builds that are stroked big blocks with the typical 4.15 or 4.25 cranks that still used heads with standard (not MW) ports?

Not talking about mild street builds, but more serious street/strip or track-only combinations. Thanks - Brad

With what is available for heads these days, the only way I can see a std port stroker combo being the preferred choice is if for some reason the big single plane manifold just doesn’t fit in well with the rest of your plans/combo.

As in........you want to run milder gearing, low-ish stall speed, a lower compression ratio, etc....... and along with those items comes a milder cam with a lower rpm operating range.

But if you’re trying to “make some power”, and are going to build a motor in the 500+ ci range, and are okay with running the appropriate support pieces....... I’d just skip right past all the std port stuff.


And then....... there will be those middle-of-the-road combos where the choice of std or MW isn’t all that cut and dried.

The most common combo I see these days is a pump gas 505 with Trick Flow 240 heads. Those engines typically make around 600 to 625 hp and are very easy to dial in for street use. The next step up is to put the TF 270 heads on there with a slightly larger cam. Then you get around 700 hp but still very streetable.

The pump gas 470 engines I did were over 700 hp with standard port 470 heads but they were more expensive than most people would build with the ported intakes, custom cams, custom pistons with 043 rings and stuff like that. I would think that most pump gas standard port engines are going to be in the 600 hp range unless they are professionally built.

If a person is willing to run race gas and a solid roller then the numbers would jump up. I'd think it would be fairly easy to make 700+ hp with a 505 TF240 combo if a person used a mild solid roller cam, 12:1 compression and a port matched TF intake. If a person wanted to hit 750+ hp then I'd recommend starting with the TF 270 heads. If a person wants more than 800 hp then I'd recommend an aftermarket block and a true MW port, probably a -1.

Not that my junk is very fast but, I have the max W ports 512cid & HAD the SP Indy intake & 3.54 gear & it had LOTS of low rpm TQ, others said ports would be to large, would it run better with 440 size ports ? dont know, but not going to try it.

The higher effort 6bbl FAST motors were around 625hp with ex manifolds and 2.5” exhaust pipe....... ported 906 heads.
No vacuum pump, stock Hemi style oil pan, non-oxygenated fuel.

Take one of those builds, use a race oriented single plane intake, add headers, and a cam to take advantage of the better intake and exhaust....... should be worth at least 50hp...... so that would put you at 675hp....... with better heads you should be able to find another 25hp...... which would put it around 700hp.
Good pan, vac pump, q16....... should add even more.

Not too many people know their port speed and I think it would help in the build.

My last trip to BIR i saw what i thought was impossible. A fellow racer i have talked to a few times ran numbers i thought were impossible. His combo; 2500 lb race wieght Cuda. 540 with max ported SR heads, pg trans. Q16 fuel. HE RAN 8.37! I pitted next to him so i had a good look at the car. Obviously this was an all out build of sorts, not your joe average bracket motor. But still, 8.37? Impressive!!
The Wallace calculater says 842 hp on that run with over 2200 DA. Granted, the heads were opened up to max wedge size, but still use rockers for the SR heads so it gives you an idea of what can be done. He said he shifted at 7400!

Brad ,
Some are aware i went down this route , 505 cnc stealth heads . Stock port size . I knew port was too small , not much more than a reasonable sbc head , so i traded off with duration . Dwayne wasnt a fan , too rowdy , Billy got it . But i chose it and daily drive it . Best et was 10.50 on the brakes , but solid low 10.50s . Which was my goal . Drive to track , swap rear tyres and air cleaner and race . So good easy power using a solid ft cam , motor was only shifted @6000 . Won track championship with that motor .
Just my 2 cents

Tex

CNC’d stealths, right?

I just finished a customers 493 low deck build...TF 240 heads, Weiand dual plane intake, 850 carb, 10.2:1, hyd. cam with around .580 lift and 240's @ ,050, on our dyno it made 596HP @ 5700rpm and 608TQ @ 4400rpm.

Yep , stock port size
Had Victor with a prosystems hp1000 4150 carb . Also tried adapter and 4500 , then super victor , stock port , and 1050 . Adapter gave poor result , AFR was all over the place . Super victor was better , more consistant et/mph . No other changes . Andys intake gasket wings were great when doing this as were the Superformance thinner gaskets .
The TF270 i then changed to were worth .25 et and 2-3mph . I opened the super victor up to suit the max wedge port .
I really need to have the stealth heads tubed on a couple of headbolts where they cracked through into the intake port , Then sell them off



Tex

Hypothetical scenario:

Take all the top end parts of a 680 HP / 600 torque 3.75-stroke combination with standard Victor heads.

Put them on a 500"-ish short block and keep the CR in pump gas territory... probably bump up the cam for the extra cubes.

What's the likely end result?

EDIT: I'm very happy with the my 3.75-stroke combination and it's a really good match for my car. I'm describing mine because it's a better example of what I was trying to ask than I think how most people understood my question.

My 511 400 stroker motor with ported big valve 906 heads with 9.25 to 1 compression ratio with the low deck Eddy dual plane six pack intake and a set of 440 6 pack carbs made 612 HP at 5500 RPM with 644 Ft. Lbs. at 4500 using 91 octane CA pump swill, that motor ran 10.69 ET at 124.+ MPH in my old Duster. Changing the heads to a set of Eddy RPM CNC ported by Jeff at MCH pick the car up .29 ET and 3 MPH, upping the compression ratio by increasing the stroke .050 changed the deck height from -.025 down to zero deck height which change the compression ratio from 9.25 up to 10.29 to 1. those two changes help the car run mid 10.30 at 127 MPH.
The last change I did was to swap the heads and intake to a set of Indy SR M.W intake ports(bump the compression rtaio to 10.78 to 1 also) and a Indy 400-3 single plane intake with a 1050 CFM Holley Dominator carb which made the car run its best ever of 9.993 ET at 134.8 MPH at Woodburn drag strip in late July the year before I traded it off for my current S/P car
More air and more fuel make more power, simple isn't it
Many people on here worry about getting to much of some good things, I don't

Sounds roughly the same as what I'd expect on the dyno here. I've never used the Weiand dual plane intake, I assume a Performer RPM would've worked a little better but maybe the customer couldn't make it fit under the hood.

built several years ago, 4.150 stroke flat top, 440 single dominator, .520 lift cam, 250 or so duration, hand ported 906 heads, pump gas, never had it on a dyno, but in a stock 1969 road runner body it ran 10.90's all day long.

Mine is probably one of the slower of the bunch here naturally aspirated but there are a lot of concessions made to make it a true street car that is easy to drive.

505" with MCH CNC ported Stealths, 10.6:1 CR and very mild .545 234/240 @ .050 hydraulic roller cam. It has a ported Holley Street Dominator intake that lets everything fit under the stock, flat hood of my '63.Dodge. 850 Demon carb and small 1 3/4" Hedman headers.

With the 11" 2800 stall converter and 3.54 gear, it has run 11.1 @ 121mph. 60 ft. not so great 1.54-ish. 3,600 lbs.and mostly stock suspension up front. It drives like a normal 440 car from back in the day with a cam and headers.

Where it COMES ALIVE is with a small plate nitrous system. Nitrous LOVES that tight converter and 3.54 gear. Still sorting but has run a 6.48 and 105mph in the 1/8 mile on 200 shot. 1.37 60 ft. Has run 10.40 @ 130 in the 1/4 mile but recently figured some things out. This the exact same way I drive it on the street. 91 pump gas, through the mufflers and on the 275 Mickeys with 18 psi. I will occasionally pull 4-5 clicks out of the rear shocks to get it to ride better. LOL.

So much fun and very little maintenence required.

I can only think of one “bracket race” std port motor I’ve done. The rest I can remember were all milder street/strip combos.

This was a new shortblock and some updates to the owners heads.
493, 14:1, medium roller, gasket matched Victor, stage 2 rpms(300cfm).
Made 615tq/665hp with a 1050 on an adapter.
The owner had just bought a new AED HO750 that he was going to using on the motor....... I seem to recall it didn’t lose much power like that..... maybe 10-15hp.

Went in a 3600lb 65 Belvedere, Cal-Tracs, 10” tire...... best of 10.20’s with the 750 carb.

First or second time out it did a pretty big wheelstand, and at the point of maximum height, it broke the pinion gear in the 8-3/4 and came crashing down.
New S60 after that.

How did the tranny and valve train do :

Motor was fine....... tranny obviously had to come apart.

From what I’ve seen, when the heads are kinda “too small”....... adding cubes and lowering the CR really takes it’s toll on the upper rpm of the power curve.
Even if the bigger motor makes considerably more tq, if it can’t carry it high enough....... you could end up not making much addition hp at all, and could also end up with a noticeably shorter usable power band.

With that type of build, the overall car/motor/converter combo needs to really be able to exploit the added tq at the beginning of the power band.