So you got 269HP at the crank? This was measured on an engine dyno? This is not Rear wheel horsepower as that will make a big difference as the 269HP sounds more like Rear wheel HP I have seen with those heads and that small cam. Do you have the dyno graph or what was provided to you showing the 269HP? Need more info.

 

Not sure why people keep using AFR 165 heads when the 185 heads or TFS heads are on the market. The claim that going to a better flowing head kills low end power is a complete myth. More air in more air out = more power .

Your cam choice isn't helping you either.

 

Something is radically wrong somewhere or maybe multiple somewheres.

It isn't the heads holding it back. The cam is too mild to take advantage of the heads properly. Compression could be low which is a fundamental build issue. The intake is too small as well. The carb may not be jetted right. The timing could have been set too low. The tri-y headers will also hold it back. It needs 1 5/8ths long tubes.


The video is not my engine. I just did a search on youtube and found it.

 

Something does sound wrong. I had a stock 302 bottom end out of a 93 mustang, e303 cam, performer rpm intake, 570 street avenger carb, and AFR165’s, and got 303 rwhp. I didn’t even degree the cam...just matched up the dots and went with it. It was my first engine build.
@happystang: Armon, I was told that the 185’s would cause PTV issues and I’d have to notch the pistons. That was from AFR directly. I really wanted them but went with the 165’s as I wanted something plug n play for my first build.

 

Something does sound wrong. I had a stock 302 bottom end out of a 93 mustang, e303 cam, performer rpm intake, 570 street avenger carb, and AFR165’s, and got 303 rwhp. I didn’t even degree the cam...just matched up the dots and went with it. It was my first engine build.

@happystang: Armon, I was told that the 185’s would cause PTV issues and I’d have to notch the pistons. That was from AFR directly. I really wanted them but went with the 165’s as I wanted something plug n play for my first build.

Jeff, my reasoning is directed towards those building from scratch where the correct pistons can be installed to utilize the better heads. In a case where the builder has the option to choose a 165 vs 185 head, why choose the smaller head?

FYI, the TFS 170 heads (which make comparable power to the AFR 185 heads) can bolt onto a stock bottom end when using the right cam, even with massive 2.02 and 1.6 valves .

Regardless, 303 hp to the wheels is great! irate:

 

where did you get the 320hp rating for th3 302 from 68? the best 302 shows a rating of 230hp, and the 390 shows a rating of 325hp. even if there was a hp 302, based on the hp 289, it would only put down about 280hp at best on fords dyno since the two engines would have the same specs except for the stroke.

as for the heads, i would have recommended the afr 185 heads, not the 165s, for the better flow and power production.

 

Get a bigger cam and have the carb and timing tuned if you haven't. If the results are still disappointing get better headers. With a manual trans you can tolerate a larger cam since auto trans and stall speed converter is not a concern. Something in the 230@.050 and .530 lift would wake that 302 up a whole bunch. You may need to replace valve springs though if higher lift results in coil bind or .060 within coil bind. Did you get the regular 165s or competition 165s? Either way, they are not your problem.


Here is perspective for you...331 with 160cc fully ported '70 351w heads making 360 RWHP@6500 in my 65 FB. I know or have known several others over the years on this site and at car shows who have used ported Ford iron with great success. It's all about the total package and not just the heads...you can have great heads but if everything else is a mismatch and/or a small cam is used and/or the carb and timing is not tuned then disappointment will arise. I have learned a lot while restoring my 65 FB between 1999 and 2004. I've been on this site since 2001 and I try to help where I can. Many new guys are conservative with their SBF build (especially if they have a manual trans) which is understandable, but I try to encourage them to build their SBF to rev beyond the ubiquitous 6000 RPM. 7000 rpm usable power with a 289/302/331/347 is not that difficult to attain...especially today with heads like yours. Guys in the 60s/70s/80s would give their right arms for AFR 165s.



My 331 history started out in 2004 making 290 RWHP with an auto trans. Tune brought it up to 306 RWHP. T5 conversion in 2005 brought it up to 335 RWHP. Rebuild with 1.7 shaft rockers, single plane intake, more head porting and valve unshrouding, reduced oil ring tension and matching the chambers to the bore brought it up to 360 RWHP in 2006. I rebuilt it to rev and make power beyond 7000 which it does. That's where it sits today. Only regret I have is that I didn't run higher compression...have 9.7 now and 11 or 11.5 would have been awesome! I drive the car so infrequently that putting Torco in the tank at every fill up would have been no big deal at all. Cam lope with high compression has a sound that is soooooo sweet! :smile2:

 

Adding to what everyone else has said:

Your intake, if it is the old-style Shelby manifold, while period correct, is designed more for mid to high-end airflow, and not really comparable to something like a Weiand Stealth, or Edelbrock Air-gap which will perform better at all RPMs. That would not hurt your peak power too much, but it will probably hurt your low end a bit.

Your carb is probably too big. That won't hurt your peak power at all either, but it may feel like a dog at low RPM/part throttle, because of poor atomization.

What is your compression ratio?

A 302 J-Code actually made 230 advertised horsepower. Probably close to what it made at the flywheel; more like 180 at the rear tires. It's a 'rare' engine, but it never was a good one; the mediocre heads, problematic 4300 Autolite carb, and 10:1 compression of the J-code made it an 'also-ran' in the real world, compared to a lot of the other 302's and 289s that got built. More than anything, the high compression and poor carburetion made it really octane sensitive.

I suspect that with some tuning, unless you're way down on compression, this engine could run a lot better. Your ignition curve would be my first place to look for more power, followed by carb tuning.

While it's true that you can make more peak horsepower with the 185's, for a street 302 the 165 heads are really well matched - especially when you're shooting more for 300-350 horsepower, instead of 400-450. They should offer really good throttle response and economy.

 

sorry for the mis spell on the hp numbers, I ment 230 out of the ford factory manual. it is the original engine to the car. had it rebuilt 10 years ago. builder said he lowered the compression to 9-1. iwas running about 180-185 compresson, now with these heads 170 or so. I called comp cams and they really didn't have much of an opinion on a bigger cam. springs in the heads were changed to match the flat tappet cam im running now. installed roller rockers with the heads. I thought the old shelby al intake wasn't a bad choice for my 302. really expected afr to help me out more as they had no answers or suggestions at all. I understand the three parts need to work together to get the most bang for the buck. I cannot afford to be trying out different combo's as I believe most guys out there. dist was rebuilt and set up by a fellow member from texas. total advance I believe was 35 degree's. still looking for that dyno sheet to post the numbers with. thanks, rich b

 

You need to figure out what your compression ratio is. A compression test is not a substitute.

I'm running AFR165's on my 347 with a TFS stage 1 cam and making 300 at the RW. Something is wrong...and I would start at CR. Depending on which CC heads you used, you could be running a super-low number now. When I first bought these heads and put them on a 289, I had to replace the pistons with a pop up style to keep it from killing my CR...and that was with the 58cc combustion chambers. I think 58 is the smaller and they also make a larger combustion chamber in that head.

I've read various magazine dyno tests on AFR heads over the years and the 185 heads typically only our perform the 165 heads by a small margin on a 302. I don't think the air flow through the heads is the issue. I highly suspect compression ratio.

Phil

 

You may well find that dialing your advance back a little will gain you power with the AFR's, because they do burn pretty fast. It is possible that you're hitting peak cylinder pressure before the piston gets to the top, which will cost you a LOT of horsepower, even if you're not experiencing detonation.

Without trying new parts, I would definitely try some tuning. Even a cell phone can log acceleration data, giving you a poor man's 'dyno' and telling you if you gain or lose power by making changes. There are even some software apps designed to help you log the info.

Your Shelby aluminum intake is 100% on style points, and still not a BAD intake. It's just very old technology, and was designed a long time before computer aided design (and better understanding of fuel-air flow, separation, and intake pulses) allowed them to create modern dual-planes. Yours was a good one. The Stealth and RPM are phenomenal. I still doubt if either would gain you more than maybe 15 peak horsepower though. They'd just help you with average horsepower a lot.

Ditto with the carb; changing it would maybe help it feel better as you roll into the throttle, and would sure help from a low RPM start - but should not change peak horsepower much if at all. I'm thinking you'll find the most power through your timing curve and total timing. If you're not satisfied after that, changing your cam to something that would play nicer with your intake would make sense to me.

 

302 afr 165 heads

dyno run results

 

Since you mentioned T5 and 3.50 gears I will assume this is RWHP, dyno measuring at the rear wheels. So this would mean the 269RWHP is 317HP at the crank. I think its the cam which is small, and your exhaust are holding this engine back. Are you driving the car or is this engine really sitting on an engine stand?

 

Better picture

 

So, a few questions would be....

1. What was your horsepower BEFORE the head swap?
2. Which model AFR165's did you select? 58cc chambers, unmilled? If so you just reduced your compression by another 1/2 point over what it was.
3. How well is your distributor advance curve tailored to your build?
4. Have you actually performed a compression test (and vacuum check)? Are you sure your valve train geometry is correct and preload isn't excessive?
5. Was your cam properly degreed when installed? The rapid drop of torque at a bit over 4,000 rpm would indicate a restriction of intake airflow above that point.

Just wondering.....

 

these are the run on the dyno with the hp and torque numbers. 236hp and 284 torque. am I right to add say 15%to the 236 to get crank hp? also how to get compression ratio with engine in the car? never done this before.

 

To do it right you have to know several factors that must be measured before you put the heads on.

To estimate it in your case though....IF (and I have no idea if this is right) your guy is right and you had 9.0:1 CR before installing the heads, you would have approximately:

8.4:1 Compression Ratio now IF you used the AFR 58 CC heads
7.9:1 Compression Ratio now If you used the AFR 64 CC heads

That's assuming you actually had 9:1 when you started and your new head gasket is the same as your old head gasket.

With a pop up piston, I was able to get to 10:1 CR using these heads.

Because IMHO either of those is too low.

Phil

 

Holy cow that thing is rich! Look at the fuel curve! It starts out a little lean, and then falls right into the flooded basement. I bet that car's making some serious fumes. Either it's just not burning the gas that's being put through (ignition timing) or that carb is just dumping. Definitely start with timing! Your torque curve is way down from what I'd expect, and the curve sucks, especially for the cam you've got, which would typically be pulling like a freight train from mid RPMs.

The way it's very gradually ramping up from 'nothing' on the bottom end to a very mediocre top end definitely points to tuning trouble. A stock 302 can usually pull right around 300 lb-ft of torque - and they poop out around 4500 or so. Your engine is making more RPMs thanks to its better springs and heads, but the AFR heads alone should put you well over 300 lb-ft! it's not uncommon to see them hit 325 or even 350 if well done. Granted, you have a mild cam, so it may be all done by 5k or so, but where's the rest of your power? Going right out the tailpipe, looks like.

Maybe it's just a case of a bad match on the intake and carb size, but you'd be silly not to chase timing and carb tuning first. And definitely start with your ignition timing.

 

That dyno graph says you’ve got tuning issues.

 

Low compression or not, your engine's dumping a lot of unburnt fuel out the exhaust.

 

If you are going to put your car on a dyno have it tuned at the same time. You are already there. If the guy doing the dyno can't tune it get someone who can.

 

Not to hijack this thread (get that A/F figured out!), but there are both static (like bearing and seals) and percentage losses (like torque converters and gears, and gears splashing through oil at different rpms) to consider. Even the math (programing calculation) in each machine doing the measuring, varies.

I think people just use percentage as it's an easy way to ballpark it, as there are way too many variables for each scenario: Dyno Manufacture and Type (DynaJet / Mustang etc.) / Rolling Dyno / Axle Dyno... Auto trans (C4? C6? Turbohydro??) / Converter Type and Stall Speed / Manual trans / rear end type / rear end ratio / what gear ratio used to test (not every car has a 1:1 choice – some dynos need this, some don’t care), and on and on.

Each drivetrain combination and every stand-alone dynamometer has its own set of unique characteristics that would affect the math (percentage).

The only way to know is to do it on both an engine dyno and a chassis dyno - but that would still only apply to your particular combo, on those two specific machines.

And then, how the engine behaves on the street or track is yet another variable, once other variable forces are entered into the equation).

Ultimately, it’s just a number. The OP needs to get the A/F straightened out, and the engine running right and then see if the he is happy with the performance (it will be *much* better than now). Then, if he’s still not happy, the next step is investigating the compression ratio, etc. If the speculated ratio is really that low, more cam is not the answer…

 

I assume dynos don't measure horsepower, they measure torque and that computer software calculates horsepower. Torque is torque, acceleration has nothing to do with it. The dyno is taking datapoints and connecting the dots, it's not actually factoring the rate of acceleration of the mass (well it is, of the dyno rollers). If you have 2.73 gears or 3.73 gears a dyno will come up with the same horsepower even though you'd have different results on a drag run, right?

 

There is an inertia factor that goes into it. The load from the dyno can be from either the weight of the rollers or from a brake or both, but acceleration of the load is definitely a factor. The load also includes the rotating mass of the car's drivetrain. This is one of those subjects that gets bantered around a lot and I stepped in it didn't I...:shrug:


Here is a link to some dyno info:


https://vtechdyno.eu/dynoblog/chassis-dynamometer-how-does-it-work.html


When trying to understand something I sometimes take an extreme view of it. For example, imagine a huge heavy flywheel connected to different engines. One engine will accelerate it at some rate and a different engine will accelerate it at a different rate. It takes more power to overcome the inertia of the flywheel quicker. The flywheel is requiring more power from the engine to spin up faster. That's how I look at it anyhow.



Sorry for hijacking the post.

 

wow a hole lot of info and questions. first off this dyno is the only one in the area. just installed last fall. I think he would prefer late model cars and trucks. we spent five hours setting up and making 4 pulls. I'm wrong again its an holley carb, 600cfm. came with 68 jets in front 70 in back. when we quit 64 in front and back. said he would order more jets to be installed at next appt. as said total time was 35btc. no nocking or ping on all the pulls. yes my original heads had 53cc chambers, the afr has 58cc.instead of having the heads milled, they would do that I went the safe route, my mistake perhaps. been trying to find the guy that built the engine 7 years ago but no luck so far, had a machine shop but no longer in business. so in order to find comp ratio I need to tear engine, heads, intake off right? then find a competent mechanic to give me the numbers. then add cam and intake to produce more hp. more money spent. yes I should have done this before I had the heads installed. some of this work is above my pay grade. been trying to find a good engine builder but few and far between in this area. don't know if I can afford another session at the dyno shop again. you guys are right, so many variables involved in engine building. thankyou for the help and ideas rich b

 

“It takes more power to overcome the inertia of the flywheel quicker.”

^ This IS torque.
AKA, twisting force.
An actual measurement of work performed.

Horsepower is the amount of work performed over time.
(RPM * Tq) / 5252=HP

Dynamometers measure torque.
Horsepower is calculated.

 

Squared up on the jetting is not typical or generally normal. There is usually a 5 to 8 jet number spread between the front and the back. There is one or two things people do when they decide to square up the jetting. They get rid of the power valve and/or they change the linkage to a 1 to 1 ratio which means the front and back throttles open at the same time and the same rate which then of course means same jetting. The usual reason for this is racing and a lot of mostly wide open running or 3/4 throttle to wide open.


What model carburator is this that you have?