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Headshot 01-01-2007, 03:29 PM has anyone used the Comp Cams racing cam that switches the 4 and 7 firing order...without any other modifications? I found the cams on page 144 of the January-February 2007 Summit catalog...just curious about it mostly...I havent heard anything about it before... Dudge_22 01-01-2007, 03:44 PM I have read mixed emotions on the performance. My buddy works at a shop that claims they get 25 more hp out of the swap. I don't know. I'll try to find some articles on it. tpi_boy 01-01-2007, 03:50 PM I buddy of mine drag races and said the engines run smoother and about 20-25hp increase. He is going to do the swap himself this winter. Bill usn-1 01-01-2007, 03:53 PM Just saw it last weekend on Horsepower TV. They did the swap and ran it on the dyno. No other mods. Same results, 25 hp on their test mule SBC Dudge_22 01-01-2007, 04:05 PM http://speedtalk.com/forum/viewtopic.php?t=130&highlight=swap There's a few pages for ya to read. odin544 01-01-2007, 07:22 PM i've also heard mixed things on this. it makes me wonder though with all the r&d going into new motors why they wouldnt incorperate it. Desertdueler 01-01-2007, 07:24 PM Chevys new motors have the 4/7 swap done already. That is why they started making cams for the old motors Dan florida4x4 01-01-2007, 09:20 PM It works best with a 7" connecting rods and a 1/2" pin height. odin544 01-01-2007, 09:21 PM oh ok well that answers my questions i would have. so it would be a straight cam swap and thats it? other than changing plug wires that is. Headshot 01-02-2007, 01:37 AM im still wondering if you matchd a crank to the cam and swapped the plug wires would u then get more of a power gain? so that one cylinder wasnt retarded and one advanced...just somthin i was thinkin about at work tonite... Bill usn-1 01-02-2007, 03:25 AM Don't know what you are referring to... But if you understand wasted spark ignition as it relates to the piston location you will know that there are 2 pistons at TDC at any one time. They are just on opposite strokes. The stroke is determined by the valve position which is driven by the cam. so in a normal SBC the firing order is 1843 6572 Note that cyl 4 and 7 are opposite of each other. Both are TDC in the cyl at the same time. Same as 1/6, 8/5, 3/2. The new cam simply swaps the lobes for 4/7 so that the new firing order is 1873 6542 The theory is that it promotes a smoother flow of air through the intake.. But it's a theory... | |