[Diabolic]

I'm hoping those in the know will be able to shed some light on question I have. I currently have a 351 with AFR 165 heads, cam is 214/[email protected] w/ .477/.444, 114LSA, GT40 FI intake, 1-5/8 Longtube headers, and a 70mm tb. The truck it's installed in is Speed Density so it is very camshaft sensitive. I'm saying that because I'm pretty set on keeping the camshaft.

I have another car that I'm considering heads for. I was thinking of swapping the 165's off the truck onto the car, 1995 Cobra. I would be in the market for some new heads for the truck. I saw that the AFR 185's flow more than the 165's but at about the .450 lift range and up. At .500 they outflow the 165's by about 23cfm on the intake, but the exhaust is the same. My camshaft only has .477 and .444 lift so I'm assuming the difference in flow is even less at that lift point. Would I benefit by upgrading the heads on the truck to the 185's or should I just leave them as they are and put the new heads on the car?

 

[Sam Vincent]

Yes, those 165's are choking that 351 to death, more or less. atleast the 185's or even the 205's. with that smallish camshaft ,would do the 205's, especially with the long runner GT40 intake. and get the lower full port job.

 

[Uncle Paul]

Wait, maybe I am goofy but 114 lobe centerline with that size motor and cam duration seem way off.
Where is the intake centerline and valve timing events?

 

[Uncle Paul]

Ok I see, a hydraulic roller in a with a efi set-up. Ok so that cam is only good till what 5000ish RPM?
If your going to keep the cam leave the heads alone. IMO for what your going to spend on heads of you don't put a cam in the gains won't be worth it.

 

[blue 79 Z28]

Wait, maybe I am goofy but 114 lobe centerline with that size motor and cam duration seem way off.
Where is the intake centerline and valve timing events?

sounds like an oem style cam to me, bet the thing idles like a stocker. the LSx cams from GM had even higher LCA in the 116-118 range!

 

[Diabolic]

The camshaft is out of a 1988 Mustang. It's the stock Speed Density HO camshaft. Certainly not ideal, but it makes plenty of pulling power where a truck needs it. On my dyno graph before the Longtube headers were installed I made 290rwhp at 4800 RPM and 368rwtq at 3900. I'm sure I'm close to the 300rwhp mark now. It's through a humongus E4OD auto trans that probablyy has a 22%+/- drivetrain loss. I'm going to figure about 355-360fwhp and 410-425fwtq.

I'm asking all of this because if the 185 and 166's flow the same up to .455 lift and my camshaft is right about .444 lift, then would it make a difference? If the lift on the cam doesn't make it up to where the heads flow different numbers, then the smaller 165 should be the same right?

 

[Sam Vincent]

sounds like an oem style cam to me, bet the thing idles like a stocker. the LSx cams from GM had even higher LCA in the 116-118 range!

He said the truck was "Speed Density" which works of MAP sensor. must camshaft with less vacuum throw the speed density for a loop. although it prob handle little more though

 

[Diabolic]

Yep. OEM, and idle is smooth and steady. Its a great turbo cam! Ha ha ha! Moves that truck to a 8.7 best NA in the 1/8th with a stock converter(1800 rpm), stock intake, smooth idle, on regular non drag radial Toyo street tires. It's my work truck. Ha ha ha!

 

[Sam Vincent]

The camshaft is out of a 1988 Mustang. It's the stock Speed Density HO camshaft. Certainly not ideal, but it makes plenty of pulling power where a truck needs it. On my dyno graph before the Longtube headers were installed I made 290rwhp at 4800 RPM and 368rwtq at 3900. I'm sure I'm close to the 300rwhp mark now. It's through a humongus E4OD auto trans that probablyy has a 22%+/- drivetrain loss. I'm going to figure about 355-360fwhp and 410-425fwtq.

I'm asking all of this because if the 185 and 166's flow the same up to .455 lift and my camshaft is right about .444 lift, then would it make a difference? If the lift on the cam doesn't make it up to where the heads flow different numbers, then the smaller 165 should be the same right?

Still think the 165 heads are too small choking the engine. if your towing then maybe just the 185 heads put some 1.7 or 1.72 rockers on with them.

is this a Lightening?

 

[Diabolic]

I actually tune it with a Moates Quarter Horse and an Innovate wideband. I've gotten decent at tuning it. I could get a bigger cam to work in theory by forcing open loop at idle, and severly limiting the amount the ISC can make airflow corrections. Might even have to lock the timing at idle so a steady 25ºbtdc. I'm confident it can be done though, just not all that interested in dealing with it. It's a daily driver.

 

[Diabolic]

Yes, it's a 1993 Lightning.

 

[Sam Vincent]

Yes, it's a 1993 Lightning.

meant something just slightly larger. maybe 218 or 220 @ .050 on intake 224 or 226 exh. on 113 t o115 L/S

small TFS cam might do well. or maybe a custom grind, Ultradyne has a nice [email protected] lobe wit h525 lift with 1.6 rocker

also Steeda has two cams both are 220/226 think ground by Crane. one is 113 L/S for fox body cars, the other is for the more finicky 94-95 mustangs its a 115 L/S.

 

[Diabolic]

The original cam was a 204/212 duration with 115LSA. I swapped to the HO cam listed above because I wanted to get away from the flat tappet camshaft design. Just the small increase in duration moved my powerband up almost 400 rpm and my 60' times immediately got worse to a 2.1. I tried everything in the book trying to get it back into the 2.0-1.9 range and just couldn't do it. Before the swap I always cut those 1.9-2.0 times and I went to the track weekly. I ended up swapping the 4.10's for 4.56's which I liked for towing better anyway. I also got my 1.9 60' times back too. I'm afraid that any more duration will result in a slower 60' time, and require me to get a looser converter which is not ideal for towing a heavy trailer.

 

[Outlaw Bill]

There is more to it than just airflow. Cross section plays a huge roll, and the 165 does not have enough cross section for a 302, let alone a 351!. I would rather see a TFS twisted wedge on it though.

Get that GT-40 intake off also, the TFS 351R will add torque and hp everywhere. Restricting airflow does not make torque.

 

[Sam Vincent]

There is more to it than just airflow. Cross section plays a huge roll, and the 165 does not have enough cross section for a 302, let alone a 351!. I would rather see a TFS twisted wedge on it though.

Get that GT-40 intake off also, the TFS 351R will add torque and hp everywhere. Restricting airflow does not make torque.

Exactly

 

[Sam Vincent]

what T.B. and headers are on it. I had a 95 lightening stock engine, put FRPP (SVO) stainless shorty headers on it, Bassani off-road H-pipe and catback kit, ASP underdrive pulley kit, 180T-stat and then bolt on 1.7 Cobra/FRPP roller rockers with slightly better springs (put air in cylinders while changing them). one time I removed the factory 65mm T.B. (FRPP 65mm) and put on a BBK 70mm T.B. and it killed the responsiveness and 60'. put the stock 65m mTB back on and got it back. what does it run?

Think mine on stock wheels/tires went 14.30-14.40 put short 28" tall radials all way around which gear it lowered and dropped atleast 80lbs rotating weight, went 14-teens then.

then later put on a S-trim went 13 flat ,then Sold it

 

[Diabolic]

I ran an 8.9 about a hundred times. Swapped to a 70mm Accufab race and immediately went 8.8. Then I richened up the mix from 800-2200 rpm to a 12.7 AFR an went 8.7 with a 1.9. 60' time.

 

[Diabolic]

I was thinking TF 192 Highports.

 

[Outlaw Bill]

Those will work also, but the twisted wedge may be better for your application.

 

[Diabolic]

TW 170 FAC?