Can anyone "dyno" (estimate) this engine?

Who's good at guesstimating horsepower (and maybe torque?) by looking at the engine and it's components?

Here's the engine in question as described by the seller:

"69 DODGE DART CUSTOM 360/727 TRANS, 8-1/4 SUREGRIP 3.55 REAR.

360 motor has standard bore/crank rebuild has a Crane .454"/272* cam, #587 heads that were cut .030", mild porting and gasket match. Weiand intake with 750 vacuum secondary Holley carb and HEI ignition conversion, quick advance dist and MP plug wires. Exhaust is headers and 2-1/2" duals.

727 trans is using a B&M 2500 Holeshot converter, transgo shift kit, 5.0 KD lever and deep pan. Rear is a 8-1/4 with a sure grip 3.55 ratio."

I'm trying to get a rough estimate on hp because I think this car has WAY more in it and that the timing and some other things aren't quite right. I'm thinking this car (1969 Dart) should be beast with that combo.

Stockish heads, single-pattern cam, and no valvetrain mods. I'll take 300HP forna dollar please Trebeck.

600 Holley should be plenty enough carb for that engine. 750, too big.

We've talked about the carb size recently. I think we both agreed it could be too much carb.

Is it large enough to think about down-sizing cfm?

I was hoping for 335hp.

My WAG was going to be between 300 and 350 at the crank, so in line with Javelin's guess and your expectations.

Is there an issue with the way the car performs? With the 2.45 first gear and the slightly over-sized carb, the car might be a bit slow to respond to a demand for more GO when asked.

Javelin wrote: Stockish heads, single-pattern cam, and no valvetrain mods. I'll take 300HP forna dollar please Trebeck.

That was my guess dangit....okay I'll play....310-ish. If it didn't crush the 8-1/4, it's not going to be an eyebrow raiser. I have an 8-3/4" housing if you want to build something. There may be a 340 2-b and X heads sitting around here somewhere also.

I haven't driven in it, only a passenger.

Seat-of-the-pants tells me it should feel much faster than my 6,000+ lb Yukon with roughly the same horsepower.

He and I think he's going to bring it to a local performance shop and get another (more experienced than we two) opinion.

wheels777 wrote:

Javelin wrote: Stockish heads, single-pattern cam, and no valvetrain mods. I'll take 300HP forna dollar please Trebeck.

That was my guess dangit....okay I'll play....310-ish. If it didn't crush the 8-1/4, it's not going to be an eyebrow raiser. I have an 8-3/4" housing if you want to build something. There may be a 340 2-b and X heads sitting around here somewhere also.

Can I forward a price on the heads, carb and rear to my friend?

fasted58 wrote: 600 Holley should be plenty enough carb for that engine. 750, too big.

You'd think that, but while trying to diagnose a stockish 289's drivability problems (it was both fuel starving and blackening the plugs, at the same time) I got fed up and yanked the Barry Grant carb off and threw my old Holley 3310 on the engine. It ran great and had great throttle response and drivability, with no tuning required

This wasn't the first time I had serious issues with BG carbs. I am thinking that they paid no attention to atomization quality. Quick Fuel, on the other hand, makes carbs that are works of art atomization-wise.

So right about the compraro of the BG to the QF I was cleaning up a QF and supprised to see 4 Circuit Metering plates in a 750 sized carb, BG's are ok for wide open but Don't seem to transition well, That 340 should run like a scalded Dog but still around 325 HP could go mid 12's with a dedecated Chassie

I'm going to say 325 crank once it's tuned up properly.

275 at the wheels.

I worked next to a dyno shop long enough to say 170-250 at the rollers and the owner will claim the dyno is broken or lying

My guess is it's still under 9.125 to 1 compression even with the heads cut. Without that being up in the 10+ to 1 range, it's under 225 HP at the wheels.

A stock '69 351 4bbl was up to 290hp. I can't see why this isn't 320 or so.

Edit: Looks like a stock '74-ish 360 was 245hp or so. I assumed it was more than that.

But a '69 351W 4V is also 10.4:1, isn't it?

My '77 LS9 350 with 882 heads was something like 175 at the crank, with a paltry 8:1 compression.

In reply to ebonyandivory:

I'm coming up with the same 245 SAE NET (not the overated gross number) for the hipo cop motor that presumably had pretty low compression on account of unleaded fuel, that's really good for a smog engine. 300+ at the crank is probably right if it was built and tuned correctly.

SkinnyG wrote: But a '69 351W 4V is also 10.4:1, isn't it?

True. It was 10.7 or something close.

What the Cliffs Notes on setting initial and total timing using the HEI with quick-advance distributor?

He just told me (has just now been able to get under the hood) his initial timing at idle looks like it's telling him it's set at 20 degrees?!?!

We're looking for 10-12 initial and what, 36 total degrees?

This isn't my specialty if you couldn't tell.

Without looking too hard it appears he shaved the heads to improve compression but left the stock pistons, which means the pistons are probably pretty far in the hole at TDC, so it's likely they have bad quench, can't run much timing, and won't make much compression anyway.

275 at the crank.

My estimate: 150 hp at the wheels.

It'll make about 200 at the crank but an old automatic with a high-stall converter isn't very efficient.

The low crank hp estimate accounts for the timing being wrong (too advanced) and the jetting being way too rich. If properly carbureted and timed it'll make 275 or so, and require 93 octane gasoline.

Small block mopar loves lots of initial timing. Mine runs 18 degrees.

You should shoot for 38 degrees all in at 3k rpm.

Lean on the primary, jet up the secondaries to compensate.

What exhaust maniifolds? In mopar, they make a huge difference in power delivery and overall power. Some were 1 7/8 actual hole size where the head pipes bolt up.....

There are too many undefined variables to give any kind of accurate estimate. The two big ones are the pistons and the head porting. We have no idea what the compression ratio is or if the porting improved the heads or made them worse.