Help

[RatDime]

Ok guys here it goes, my truck ran great all last year, I installed a electric water pump and a set of alum heads with bigger valves and runners, the heads were used but very very low miles. The guy had a roller set up with low lift (.530). my cam is about the same lift, the heads have duel springs good for .600 or so. Anyway, when I drive this truck it revs really good, but under a load inwhich this case, it will not go beyond 35-4000 rpms and then it starts coughing, spitting and lil backfire out the exhuast. the cam is good for 7500. I have re-ran valves, reset timing(36 total) jetted it back and forth from rich to lean and back to where it use to be, everything, what am I missing???

[mytmouz]

Is your cam a roller also?

[RatDime]

no hyd ft

[dand355]

your spring s are too tight. your going to wear that cam right out of there. changes the springs, as your motor rph'ms up the springs get to tight. the lifters may colaspe, stop running it your going to hurt somthing. others may say the same or not .hydo cams and roller springs don't work to gether. i know nothing much but talk to the others . good luck

[dand355]

ratdime did you call mike about the gear ?

[mytmouz]

Dan nailed it, you have too much spring pressure.

[434 smallblock]

X3 you better not run it it will eat the cam and fill motor with metal

[RatDime]

No I left Mike a pm, he has yet to reply to me. I wouldn't think the springs would be too tight. But I have not thought about it, others are saying ign and air leaks, but all of that is good.

[434 smallblock]

the seat pressure on a roller spring is anywhere from 250 to 300 lbs of seat pressure the lifters are collapsing thats why you are hearing the pop just like the cam is going flat.

[RatDime]

thanks guys, I just peeked at my cam card and its only calling for 120 of seat pressure----yikes, better get them off now!!!

[434 smallblock]

rat go to chat

[RatDime]

alright I changd the springs out, got the correct ones, checked the lifters and cam lobes-all good. Got it back together and it still does the same thing, whats the next step-this is gettting frustrating

[dand355]

hmmm........ well at lease the heads r right .r you using the right plugs long or short my dart pro's use long plugs. did you shim the springs ? what ignitoin are you running, hmmm...

[dand355]

i read your last few post, it sounds like ignition now, check your dis cap look for cracks , may have a bad plug wire arcing on header, check timing again , trial and error check every thing again and again. it's something you did when you swapped over the heads . it might be something you over looked . take your time it'l pop up

[RatDime]

Im usinf autolite racing plug 3935, I might switch to ngk b8es, The dist is a accel I just got from mike, all brand new. The wires are8.5 super conductor msd. I am just going to have to start from page 1.
However I did drive it 1 time last week after the spring change, I was able to take it to 6 k or so But I had to accelerate slowly up to it

[dand355]

are you using a msd box

[RatDime]

no, just the accel hei and super coil. vac advance is wacked off

[tomcat]

hum sounds to me like inition problem 1 st off what is your timing totaled at? 2 nd is the cam degreed if so is it correct. ok here is what i would do and i think it will tell you what your problem is. Just stick a standard hei disturbor in it and total the timing at 36 degrees. if it is not leaning out. it should clear up. what is your fuel pressure. what type of pump filter and cell?