Advice on a 440

dcassellia

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Hello all I'm asking for advise here is my combo

1968 440 stock short block
Trick flow 240 heads
Mancini rocker arm 1.5
Comp cams XE290S intake lift .540 ext .558 290 intake 298 ext duration
TTi headers
3500 stall
391 gears

In a 71 scamp

Now my questions 1. can I run 1.6 rockers and will I have any issues
I think it will bump the lift up to .576 int .595 ext
I'm concerned with the ext lift hitting piston

2. What is the biggest cam I can run solid roller cam
 

TT5.9mag

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What is the deck clearance? How much piston to valve clearance do you have now? These are the type of answers you’ll need. You’ll never know till you measure it. And lift isn’t the problem, duration is usually what causes P to V contact.
 

jbc426

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Hello all I'm asking for advise here is my combo

1968 440 stock short block
Trick flow 240 heads
Mancini rocker arm 1.5
Comp cams XE290S intake lift .540 ext .558 290 intake 298 ext duration
TTi headers
3500 stall
391 gears

In a 71 scamp

Now my questions 1. can I run 1.6 rockers and will I have any issues
I think it will bump the lift up to .576 int .595 ext
I'm concerned with the ext lift hitting piston

2. What is the biggest cam I can run solid roller cam

You will need to mock up the engine with the head gaskets you are going to use and verify the clearance. You can use clay then measure the distance between the valves and piston top.

You do realize that the largest cam you can get away with may not match your combination, right?

I would get some input on which cam matches your combination from a guy like Dwayne Porter.

What is the duration at .050"?
 

Bewy

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Another method to check V to P clearance without clay. Assemble head with light springs, just enough tension to hold the valves in place.
Instal head with gasket [ or equivalent thickness ]. Install prods, set lash etc. Slowly rotate engine until both valves are open at TDC. Push the rocker down & that is your clearance. You can measure the distance with calipers. 0.100" int & 0.125" exh are safe minimums. If you are close to these numbers, then the int valve should be checked a few degrees AFTER TDC & the exh checked a few degrees BEFORE TDC.
 
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