i have a custom grind comp cam xfi
236/242 .615/.612 112lsa +2

i was wondering if this cam would be too big for my ls1 with my 5.3 ported heads?

just wondering one some opinions on what would be best for that set up.

 

PTV clearance may be tight.

other than that it should perform well.

 

you think it would be anything too worry alot about?

 

with that big of a cam...similar to the MS3 from TSP

i would be worried enough to check.

really depends on what was done to the heads...milled, bigger valves installed, or installed with a thinner gasket.

 

i mean i'm not gonna stick it in and crank it, i'm gonna turn it over by the crank slowly and make sure they don't hit. the heads will just be ported, nothing special like bigger valves. i might mill em enough just to get the warp out of them if there is any.

 

what do yall think would be a good size cam for a stock 98 short block ls1 with ported 5.3 heads and an m6?

 

What size are the chambers on the 5.3 heads? Remember they start out with like a 62 cc chamber unlike the regular ls1 heads 66 cc chambers. With the 5.3 heads I would try to stick with a cam with a 230 or less duration. Other wise you will be fly cutting the pistons. Just because you turn it over by hand and they don't hit don't mean they will clear at higher rpm. You realy can't tell anything by turning it over by hand anyway. If I were you I would plan on checking the ptv clearance or just get a cam with less duration.

 

i probabaly will end up getting another cam anyways.

but they are 706 castings

 

how you think a 234/226 .595/595 reverse split cam would do? or

224/228, 581/588, 113+2



this will be an n/a motor anyways

 

go with the comp 224/228,good proven grind makes great alround fun
enjoy
cheers dave

 

all the cams suggested are good cams....but they are for different goals.

what are YOUR goals?

either rwhp or track times.

a 23x/24x cam will make a significant amount more power, at a different point in the rpm range than a 22x/22x cam will.

with your given heads, the smaller cams should put you easily in the 400-420rwhp range. the bigger cam should put you closer to 450rwhp.

but its gonna rev higher and be a little more touchy around town. but with a good tune it should drive fine.

 

which of the two smaller one do you think would perform better?

the
234/226 .595/595 reverse split or

224/228, 581/588, 113+2



i'm looking for around 400rwhp is my goal and i'm not worried too much about drivability cause its not really my dd.

i mean don't get me wrong. i'd love to use my big cam but i don't want to risk valves slapping the pistons.

i'm asking cause i will prob trade my big cam for one of these.

 

my cam makes some huge power and has great driveability...

also throwing a cam in and just turning the motor over is not a way of checking PTVC...you could have .001 or .120 clearance...

 

x2 it may clear when the motor is cold but once it heats up we could have a problem

 

how do i check this then?

 

if you dont wanna pull the heads get a checker spring and use it in the valve... bring the piston to TDC and with a micrometer measure the clearance...do it a couple times to make sure...

if pulling the heads i recommend just claying the piston...

 

agreed

 

hmm, what do you mean by claying the pistons?

 

if pulling the heads get some model clay and put it on the piston u are going to check...reuse the old head gasket if u are using a .040 cosmetic dont forget to subtract that from the measurement...put the head back on with 4 or so bolts and crank them decently tight...turn the motor over a couple times but the crank bolt...remove the head and u should have two eye lid marks from each valve...carefully scrape the clay off of the piston and bisect the clay to the smallest point for each valve...take a measurement with a caliper...for the intake standard safe practice is .080 and for the exhaust is .100...although some people run a little tighter with some of the bigger cams out there...but that is a whole different thread...

Chris

 

my cam 230 230 with .612/.591 lift on a 111+2 had 0.086 intake and .120ish exhaust...this is with stock mls gaskets and stock untouched 241 heads...