Running an XFI camshaft on a carburated engine?
05-13-2009, 12:43 AM
#1
Le Mans Master
Thread Starter
Running an XFI camshaft on a carburated engine?
I've been offered a comp XFI (Xtreme Fuel Injected) camshaft from a forum member for free to use in my carburated 350. What are the downsides to doing this? Will it run at all? or is there only a slight decrease in performance. The specs are listed below:
Intake Exhaust
Gross valve lift .499 .493
Duration @ .006 tappet lift 260 272
Open Close
Valve timing @ .006 Int. 21 btdc 59 abdc
Exh. 73 bbdc 19 atdc
Cam installed @ 109.0 Intake center line
Intake Exhaust
Duration @ .050 216 223
Lobe lift .3120 .3080
Lobe separation 113.0
I can't imagine why it wouldn't work. The lobe separation is a little large but that should help smooth out the torque curve right? everything else looks normal though (to my completely untrained eye).
Anyone run a FI camshaft on a carburated setup?
thanks
Intake Exhaust
Gross valve lift .499 .493
Duration @ .006 tappet lift 260 272
Open Close
Valve timing @ .006 Int. 21 btdc 59 abdc
Exh. 73 bbdc 19 atdc
Cam installed @ 109.0 Intake center line
Intake Exhaust
Duration @ .050 216 223
Lobe lift .3120 .3080
Lobe separation 113.0
I can't imagine why it wouldn't work. The lobe separation is a little large but that should help smooth out the torque curve right? everything else looks normal though (to my completely untrained eye).
Anyone run a FI camshaft on a carburated setup?
thanks
Last edited by IcemanZ06; 05-13-2009 at 12:52 AM.
05-13-2009, 01:06 AM
#2
Le Mans Master
The XFI series is IMHO a very good line of cams, and should do just fine with a carb, as long as the selection otherwise matches the application (heads, CR, your purposes...). The wider 113* LSA than many CompCams Chevy grinds (110* being fairly common) may cost a touch of peak torque/power vs. what that same cam might produce with a narrower LSA, but you'll pick up some bonuses such as a wider power band, better idle quality and increased vacuum. IF this all sounds good, go for it.
Of course, you've left out some important details (particularly your current basic engine specs), so this observation is highly speculative.
TSW
Of course, you've left out some important details (particularly your current basic engine specs), so this observation is highly speculative.
TSW
05-13-2009, 01:17 AM
#3
Le Mans Master
Thread Starter
The XFI series is IMHO a very good line of cams, and should do just fine with a carb, as long as the selection otherwise matches the application (heads, CR, your purposes...). The wider 113* LSA than many CompCams Chevy grinds (110* being fairly common) may cost a touch of peak torque/power vs. what that same cam might produce with a narrower LSA, but you'll pick up some bonuses such as a wider power band, better idle quality and increased vacuum. IF this all sounds good, go for it.
Of course, you've left out some important details (particularly your current basic engine specs), so this observation is highly speculative.
TSW
Of course, you've left out some important details (particularly your current basic engine specs), so this observation is highly speculative.
TSW
05-13-2009, 01:19 AM
#4
Melting Slicks
If this XFI cam was from a newer "roller motor" then it will not work in your older non roller engine. The nose of the cam is different and must be mated to the matching cam timing chain gear which is designed to only fit a roller block.
05-13-2009, 01:22 AM
#5
Le Mans Master
Thread Starter
05-13-2009, 10:23 AM
#6
Race Director
The XFI series is IMHO a very good line of cams, and should do just fine with a carb, as long as the selection otherwise matches the application (heads, CR, your purposes...). The wider 113* LSA than many CompCams Chevy grinds (110* being fairly common) may cost a touch of peak torque/power vs. what that same cam might produce with a narrower LSA, but you'll pick up some bonuses such as a wider power band, better idle quality and increased vacuum. IF this all sounds good, go for it.
Of course, you've left out some important details (particularly your current basic engine specs), so this observation is highly speculative.
TSW
Of course, you've left out some important details (particularly your current basic engine specs), so this observation is highly speculative.
TSW
I read your other post. With a stock L48 bottom end and 65 cc AFR 195 heads if you use a .015 gasket (http://store.summitracing.com/partde...4&autoview=sku) you will have just under 9.5 to 1 compression ratio, about 7.9 to 1 DCR and .040 quench using the info I have. This combined with your RPM intake, cam specs and the lift (almost .500) will work well with your 195 heads,(a little big) and make a streetable combination that will supply good power and probably run on 87 or 89 octane. Just be careful on oil choice and break in with the fast ramp cam. You have to have over 1200 PPM of zink and phosphorous or it won't live. 1400 is better.
Last edited by 63mako; 05-13-2009 at 11:04 AM.
05-13-2009, 10:43 AM
#7
Le Mans Master
Member Since: Sep 2000
Location: DFW TX
Posts: 9,078
Likes: 0
Received 7 Likes
on
4 Posts
Cruise-In VII Veteran
St. Jude Donor '07
FI cams will usually have a 220 duration at .050 for a stable MAP signal. Not a bad thing to have since it will help with vacuum. Motor will be easier to drive with an automatic also.
05-13-2009, 11:10 AM
#8
Race Director
My 72 had a TH400 and 3.08 gears. Your cam will match well with that. When you build the monster motor in the future gearing changes will be needed, either trans or rear end or both.
