sportsman200 vs 215 iron platinum

[stroker383ci]

well i try my truck at the track today and i guess i didnt do my study ...i was running 12.00 last years and didnt be able to go lower than 12 46 today i guess those sportsman was running not bad .....:eek: engine 383

[Trmnatr]

well i try my truck at the track today and i guess i didnt do my study ...i was running 12.00 last years and didnt be able to go lower than 12 46 today i guess those sportsman was running not bad .....:eek: engine 383

Give info on entire engine, trans and rear then we can help

[stroker383ci]

373 rear end th350 tranny .air gap intake .26 inch drag slick ,s-10 short box truck,flat top piston ,solid extreme energie cam, 520 540 110 lobe from competion cam...same set-up just switch head to the new iron egal platinum not alluminium

[Awesome Bill]

If all you changed were the heads, then you may have something not the same. I would recheck everything before shooting the horse. Too large a head should ot kill it ½ second. Its possible but not probable. If your sportsman were 180 to 200 cc's, you had plenty of head. Just by changing out to the Platinum heads over those already good heads would only yeild you around 10 maybe 20 hp. If you had stock smog heads and your upgraded, you would see 50-75 hp. When you already have good heads, you will only see 1-5 hundreths at best. If you gain a 10th, you really do good. In this case, you pretty much could have something just not exactly like you had before to loose that much!

[Trmnatr]

The cam "In My Opinion" is a little too small for a 215cc runner head on a 383

[stroker383ci]

well ill try to see if i did something different but i don't really think ... maybe those 215 are to big and make me loss some power... i know haft of a second its not that mutch but i hit 108 this year and 112 last years mph .. something let me think that motor doesnt make the same power with the new desigh heads

[Trmnatr]

With a .500 lift cam the sportsman II's had good port velocity because you were at or near max flow. Switch that bad boy to a solid roller with that duration or a bit more and make sure its .630-.680 lift and you will see much power

With your cam you should have went with the 200cc platinums but then you would have needed some new eye balls aftering going W.O.T because you would look like this :eek: then you would do this :D

[stroker383ci]

i got a 555 lift solid roller with 108 lobe ...ill try that next year with the same set-up will see if its better but i need to open the motor for rod clearance

[Trmnatr]

I have found a tighter lobe seperation 99 out 100 times ET quicker in a small block

Try a 106° solid roller if N/A.

[stroker383ci]

i check everything and i notice more rocker arm clack noise .. i check clearance and not sure why the clearance switch around 0.024 and was set at 0.015 ...all rocker was at that specs sounds weird ... those are new rocker ...any one think they could be bad stuff... doesnt sounds like a cam failure .not on every lobe well i think

[Awesome Bill]

Its not your cam or any other thing like that. If you run those times last year and all you did was change heads, then something you done from that point has changed. You would not loose 75 hp from changing the heads out. How far off are your 60 foot times from last year? What was the combustion chamber on the other heads and were these 64 or maybe larger? The very least you should have to change is the converter. If it was fairly tight, under 2000 rpm, when the larger heads were put on it killed the bottom end and when you shift, if pulls it back down and is very slow in pulling back up. So I would start to back track and recheck what I have done. The larger heads and most likely larger intake valve will kill bottom end and torque. But, if that were the case, you should feel a really strong power band a little higher up. Most likely, something is not adjusted correctly.

[Awesome Bill]

Tighter lobs only make the power band tighter and will most likely peak in a narrower torque curve. Heavy cars and trucks, like 108-110 in street applications and do very well in his application. I have used even 112-114 and never lost the power he is speaking of.

[Awesome Bill]

You need to make sure each valve is opening and closing correctly and at the same lift. It is possible you are loosing a lobe or 2 and is not uncommon if you got some heads with a little more seat pressure the cam and lifter can handle. Check there first. You can put a slide rule under the rocker tip and let it hang on the edge and turn the engine over and see what the lift is. Should be pretty close on all!

[stroker383ci]

thnx ill try to see if the cam is burning down ..but on eatch lobe ??
well i rate the spring and set them the same it was running on the sportsman .same heigh same pressure

[lun40119]

I dug through some old threads, weren't you running a flat tappet with the sportsman heads, and now you are running a mech roller. I would think you would have to change springs.

I agree with Bill something isn't right. You should have been at worst, slow on the bottom and quicker on top. Like he said, retrace your steps and see what is different.

Jake

[stroker383ci]

no still got a solid flat tappet cam.. try to find why the lash increase every where ..
i know with a roller cam i will need to switch for bigger spring .. i didnt put the roller solid cam beacuse of the clearance issue with the connected rod

[stroker383ci]

well i did the same 60 feet motor doesnt seem to have less torque i think it have some more but after .............

[want-a-be]

Did you install a new timing chain when you changed heads? If so did you degree in the cam? What is it installed at?

I see you're running an Air gap intake. Are you sure that the intake is sealed properly? Might check that. Take your carb off and look down all the runners. Do you see any oil at all in the runners? If so then you've sucked in your intake gasket on the bottom of the intake runners.

Myself I don't like the duel plane intakes for performance engines. Never seen one keep up with a good open plenum intake. JMO. Might consider an intake change. Especially if what you have isn't big enough to seal the new heads.

Don

[lun40119]

If it is a flat tappet, and your rockers were loose by .010, I would definately start looking, check the lift at the valve, or your oil, bet you find your 4mph.......

Do you drive this alot, I would think if you have any miles on it at all, it would be running like crap, and backfiring if you were loosing some lobes.

Jake

[want-a-be]

no still got a solid flat tappet cam.. try to find why the lash increase every where ..
i know with a roller cam i will need to switch for bigger spring .. i didnt put the roller solid cam beacuse of the clearance issue with the connected rod

It's been my experience that most of the wear on a cam will be on the toe of the cam and not on the heal of it. Check the lift of the lobes and see if they are where they should be. What spring pressure are you running on this thing again? If the lift is where you left it rerun the lash and try it again. Are you running a stud girdle? 7/16" or 3/8" rocker studs?

Don

[stroker383ci]

5/16 studd with studd gurdle never had that problem last year with those sportsman ...if my memories is good seat pressure are set at 125 ..i will need to look in my book to make sure

[lun40119]

Doesn't matter what the book says, check them. Over time they loose pressure. I think I have 3 or 4 sets on the solid cam I have been running for 3 yrs. 3/8 studs or 7/16 studs.

Jake

[stroker383ci]

my bad 3/8 studd not 5/16 lolll... well i check them at the shop at set them i'm pressure to 125 .. not spring book my note book

[stroker383ci]

i agree with the intake air gap the port seem not big enough for the heads

[stroker383ci]

i did ajust the lash again to .015 will see if it move again

[Trmnatr]

Tighter lobs only make the power band tighter and will most likely peak in a narrower torque curve. Heavy cars and trucks, like 108-110 in street applications and do very well in his application. I have used even 112-114 and never lost the power he is speaking of.

With a larger engine maybe ! I do not agree with a smaller engine such as 283, 302, 327, 350 and some 383/406's

I can show you at least 5 small blocks that ET quicker with a tight lobe center, With a POWERGLIDE which wants a "wide" powerband.

In my own 406, a 105° over a 112° gained 2-3mph and ET's well over .2-.3, This is hard to say as the cam made it run .2 quicker then the carb size change it went .1 quicker, then the gear change it went .2 quicker for a best of 6.59 @103.55mph in the 1/8 and a 10.41 @127.44mph

[stroker383ci]

well i reajust all the lash will see if it move again its my every day truck so ...:rolleyes: