jap901

Hello I like to know what injector size & compression I should run with the xfi 292 cam and what else should i upgrade.

I have:
ported stock lt1 heads, should i cut them for bigger valves?
ported lt1 intake 58mm ttb,
Pro comp 1.6 roller rockers
LN0018DBLAS Lingenfelter LT1 L98 SBC V8 Double Valve Springs

stock lt1 crank, upgrade?
stock rods, upgrade?
stock pistons, upgrade?

6 speed trans and 4.33 rear gear

Thanks Jim

96capricemgr

Comp's rpm range is WRONG, you are going to have to spin that much higher than their catalogue says.

High enough that the stock rod bolts in particular are a real concern., frankly spinning that high that often I would start to worry about the pistons cracking around the pin. I have one out in the garage from an M6 car cracked and I think RPMs were the cause.

By bigger valves how big do you mean? 2.00/1.56 is most common upgrade in LT1 heads but the bowl work has to be done with them in mind, if the heads are already ported you will be looking at having to send them back for a touchup.

I don't even have to look them up to tell you thois springs will NOT work with this cam. The XFI stuff was designed specifically to take advantage of the capabilities of beehive springs, guys have tried and failed to control smaller XFI lobes with double springs.

IMO the XFI stuff is a poor choice in general, and this one in particular does NOT belong in a 350/355.

If you want to rev to 6800rpms or so then maybe consider the 847 but frankly I see no need to go that big unless you are doing a full build with these rpms in mind. If you looik up the 847 it's duration is a good bit lower than the 292 and it will still need to rev it to 6800rpms easily.

Not the answer you wanted but better to find out now then chase issues after.

Kaj

I've seen only two cars handle the xfi292, and about a dozen others that failed with this cam.

speed_demon24

Way too big for a stock displacement motor.

jap901

[QUOTE=96capricemgr;5276222]I don't even have to look them up to tell you thois springs will NOT work with this cam. The XFI stuff was designed specifically to take advantage of the capabilities of beehive springs, guys have tried and failed to control smaller XFI lobes with double springs.QUOTE]

The LN0018DBLAS Lingenfelter LT1 L98 SBC V8 Double Valve Springs are good for .630 lift. when the xfi 292 has max intake lift of .584

thanks for all the info

speed_demon24

[QUOTE=jap901;5276283]If you think that just because the spring can handle the max lift that it can handle the cam you need to do A LOT more research before you start buying parts.

jap901

[QUOTE=speed_demon24;5276659]Well educate me! Because I don't understand. The lift is less on the cam than the valve springs are rated for.

thanks For the replys

96capricemgr

The rate of lift has to be considered too.

Think about it like hitting a speed bump at 5mph and then at 10mph, the size of the bump does not change but at 10mph I bet you hammer the bumpstops. Similar sort of thing goes on with cams, springs have to be taylored to how hard the cam is going to hit them not just how far it will compress them.

mdacton

[QUOTE=jap901;5276703]its the "ramp" on thelobe to keep it simple...the XFI stuff is kind of nasty so its not as easy to control. It was designed for a purpose as stated.....for the behives.

Find another cam.....your going to be dissapointed going with this and it will never run right.

jap901

Thank you for the lession.
I don't have a cam yet, i just read a few post on here stating it had a better torq down low than the cc306 is why i was intersted.

I guess I will stick with the cam i was thinking of using. the Comp Cams "Extreme" LT1 Camshaft, 230 / 236, .510 / .520 112 LSA

1badasZ

I guess I will stick with the cam i was thinking of using. the Comp Cams "Extreme" LT1 Camshaft, 230 / 236, .510 / .520 112 LSA[/QUOTE]

it is an ok cam but i wish i had spent the extra money and went with a LE2 or something of that nature. but dont get me wrong its a nice cam and pulls hard to redline but i havent gotten to use it much cause ive been having issues with my car