Thread: 351 build

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I am in the process of building a 351windsor on the cheap to thrash at the local strip. I have been working with a local speed shop and just got my heads ported and set up for up to .600 lift. I am thinking about using a comp cams hydraulic flat tappet cam instead of the retro fit roller that the shop is suggesting. They are good folks, but they don't have the budget restrictions that I do. My question is this-on a strictly horsepower sense, just how much power am I going to lose by going this route ? The cams spec out very close to the same in terms of duration and lift as well. I understand the difference in the two in theory and know there will be some loss going with the older style hydraulic cam. Also-the springs I have installed are 27 lbs. heavier open than what is suggested for a hyd. cam-will this pose a problem or am I stuck with going high dollar roller now?? Any help very much appreciated!

Refer to Comp cams in regards to roller vs. tappet. I don't think flat tappett would give up any to a roller design if properly let up and it is a lot cheaper. I have seen several flat tappet cams run some very good numbers but I'm no cam expert. If Comp Cams says it will do it it will.

The 27 lbs heavier springs will be fine, don't worry about it.

I would suggest contacting the manufacturer of the cam you want to use and verify what weight springs they recomend for the particular cam.
Too light of a spring can result in a loss of rpms and power due to valve float while too heavy of a spring can result in premature cam and lifter wear and quite possibly breakage.
While the roller cam can free up a lot of horses due to friction loss, it isn't neccasarily required to make big power, so get what you want and at least get everything for the cam matched up so that it will last longer and take advantage of all the power that the cam has the potential for.

Tech : The block was set up at zero deck with wiseco 11.2 : 1 forged slugs. I was told that it is possible I will have to have the pistons clearanced for the valves. Since I am trying to keep costs down where possible, it seemed to me that higher compression pistons were no more costly than lower comp. pistons-except the decking of the block and possible notching of the pistons. Hopefully I will see a few extra horsepower from the added compression......

Thanks for all thre info- I just might try the notching myself-seems a little scary but nervous slow and steady should do the trick !