Looking for someone who is experienced with camshaft specifications and how these specs affect performance. My '49 Ford F1 has a Ford 302 / 300HP crate motor from ATK. I'm disappointed in the loping idle and the low vacuum at idle (13"hg @ 850rpm) in drive. The camshaft specs are as follows: 219/219 @ 50, .498 intake/.498 exhaust 110 LSA. The motor is fuel injected (Edelbrock ProFlo4) and runs fine with the exception of the idle issue. The stock heads were replaced with a pair of AFR 1399 street aluminum heads. My question is should this camshaft with the 110 LSA cause the idle issue or should I be looking for a leak somewhere. If the cam is the issue, what LSA usually gives a smooth idle and at least around 17" vacuum at idle. My power brakes are a bit weak with only 13"hg to the booster. Thank you in advance for any ***istance and info.
That's a lot of lift for a small displacement, and the LSA isn't helping. I'd guess that it also is kind of a dog off the line and really starts pulling around 2500-3000RPM. A smaller cam would definitely help with idle vacuum. https://www.vintage-mustang.com/threads/cam-for-stock-302.972809/ Stock for a '68-75 302-2 is...... Lift .368 int/.381 ext. Intake valve opens 16 degrees BTC and closes at 70 ABC. The exhaust opens 44 BBC and closes 20 ATC. Overlap is listed as 36 degrees. I will suggest calling a cam company that meets your comfort level for quality, cost and service. Ask them what your best choices are. Be prepared to provide engine size, compression, inlet and exhaust info, weight, trans type, rear gear, tire height and intended use. They have sold more cams and hopefully got more feedback than just about anyone here has tried out.
You're probably right even though I thought I was buying a "street" engine with a little extra HP. They offered a 345HP 302 and I stayed away from that one to try and get a better idle / vacuum. Not that this makes any difference at this point.
Thanks, I was hoping not to have to pull the camshaft to replace it but I was afraid that would be the best choice. I guess I'll run a smoke test to make sure I don't have any leaks and if all looks well I'll start looking at a different cam. ATK claimed this combo should idle good but it isn't the first item they ended up being incorrect about. Live and learn . . . Thanks for your opinion!
Getting rid of the power brakes is not an option due to the disc brakes on all 4 corners. I have contemplated the vacuum pump idea and would have to balance that option versus the camshaft option. I don't really need the higher HP since this is in a '49 Ford F1. If I want HP, I jump in my 2000 Lightning which idles better with good vacuum and is extremely quick (it's supercharged!) compared to the F1.
hmmm...I have manual 4 wheel discs on my 62 Vette, no need for a power booster. But we all see things differently.
110 LSA is lopey but not terrible. Verify for vacuum leaks and if none found a vacuum pump is cheaper and easier than a cam swap. https://www.summitracing.com/parts/...h-VlWZP6UmDu6sACKZD35h1ObY02ZItxoCOGQQAvD_BwE
I think you will be changing the cam. Most of the later model cams are 114 lc. If you can find a stock Mustang gt cam, i would try that ***uming you have a late model roller block. As another thought, if you don't have an adjustable proportioning valve, install one. shut the bias to the rear a lot and you may be pleasantly surprised.
Good suggestion if I decide to change the cam. I don't have an adjustable proportioning valve. Sounds like another great suggestion. Thank you!
What is your problem with low vacuum. Is it gutless down low? or poor vacuum for the brakes? If it is just the brakes. Use an alternator of a Japanese Diesel engine with a vacuum pump on the back. [these things can "**** Start" a Harley engine] Buy a multi-keyway timing set and advance the cam 5° [or as far as you can] I'm a real fan of tight LSA it helps the engine pull hard from down low. Wider LSA is normally used to "fix" too much duration. There are a few other tricks you can do to the valves to mask valve overlap.
Power ***isted brakes are NOT...a requirement when using disc brakes... I have three cars with 4 wheel disc brakes, and NO power booster on any of the three ! You just need to read up on how to build a brake system. And NO again. Your .498" lift IS NOT too much lift. Lift, in general will help overall power...without...too much in the way of ill effects, like the lobe center angle. A 113 or 114 degree cam will give you a smooth idle and your vacuum back. LEAVE the valve lift as is... Seems that you've just put together a combination of parts that don't like each other. Will not play well together ! And the 110 lobe center angle, yes, that IS lowering your vacuum. A car that I'm working right now has 108 degree lobe center angle cam. It's only got about 8 in. of vacuum !!! Mike
Aside from the heads, this combination came from ATK crate engines. Yes I did put too much faith in their expertise and I would never use them again for this reason and a few others. Getting past that, I was not trying to build a race truck but a good looking weekend driver with a bit of pep. Having it comfortable for me to drive was important which is why I stayed away from the higher horsepower variants and added power brakes, power steering, and A/C. Thanks for the camshaft info as I will admit I am no expert on camshaft grinds aside from what I read. I appreciate you guys who have the practical experience and can help guide me on what to look for.
Wow, I was not aware of an alternator with a vacuum pump. Might be an acceptable solution to the vacuum problem. I will check into the multi-keyway timing set as well. Thank you.
I’m a little bit surprised that a 300 HP engine came with a .498 lift cam ,,,with that much duration at .050 . I am pretty certain the engine should have a lope at idle with that cam,,,,,,and 13 in of vacuum isn’t bad . I know the old factory engines with 300 HP didn’t have a cam anywhere near that . Sounds like a lot of cam for such a low rating . Tommy
Here is a Mitsubishi L200 Version, But every Japanese Diesel SUV , Pickup , Van has one Advancing the Cam is a dirt track racer trick They need to pull off the corners and race in one gear. [I also did this for Road Racing] My 454 race engine made 90hp while idling at 900rpm with an advanced roller cam [it had 105° LSA] The torque went up and the hp doubled at 1600rpm If you are going down this path , give your engine a compression test before you start. Then compression test later.[and watch it climb] When the compression [cylinder pressure]starts dropping off , you have gone too far.
Maybe change brake ratio ?! Cam How about the Ford Motor Sport cams around 1992 ish Mustang or SVO cams line, Rollers Off top of head , E303 EFI Cam I Believe there was also a B
You could also install a hydroboost in place of your vacuum booster. I did this on a car recently and would never go back to a vacuum booster, the braking is better and there is more room in the engine compartment. A few more hoses but those can be arranged neatly.
I was suggesting a two-part question,, Brakes , Look into different break ratio, Its 49 F, many times build / install wrong mismatch brake parts... Op had a question on a Fuel Injection motor, Sounds like he did not like the camshaft sound /disappointment and the performance . Just suggesting the camshafts that were used around 1990 through 94, In the Rustangs , many Rustangs using the 303 cams Again off top my head there were several different versions of 303 FMS /SVO line / catalogue, With the wright tweaking ,( stock tps , chip ext) Shorties , 7:40s 1/8 was a fast Ride for a street driven dayley, sbf fuel injected before 1993 . & with a little spray of gas 7:Os -20s , Killer comb , In those years , The Rustang had its own unique sound with the set of flows, & No , known Issues with the brakes with those cam's
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