shortpump

I hope I got this thread in the right place, anyways I need some help and judging by the forum you people know your stuff on these motors. I Have a 2005 Silverado 1500 with the 5.3l. Transmission just blew and while it's in the shop I want to add a few horses to the pony. Currently all I have is a programmer, cold air intake, and throttle body spacer (pretty much stock). The transmission going in is a level 3 from transbuilderguy with a FTI 3000 stall. So on to my question:


I just picked up a set of 706 heads that have been ported, polished, and shaved .060. They also came with beehive springs.


I'm looking at a "***** thumpr" cam which is a 227/241 with 109 lobe separation. This cam requires 9:1 CR, 2500+ stall, intake, gears, and headers.


Will this cam and head combination work together?? what else do I need such as lifters, timing, rocker arms, push rods, valve springs??


I'm new to this but I've been doing a lot of research, fullsizechevy can't seem to give me any answers. Any other advice is welcome. I appreciate yalls help in advance!

bobfig

first of all did you shave .060" or .006"? if you did the .060" you may of gone to far and bumped that compression way high not to mention how close the piston to valve may be if not hitting it.

as for the came to me thats a little high for a truck and you would have little low end.

ls7 lifters are a good idea
stock rockers are fine
5/16 hardened chromoly push rods (measure to get size)
springs would mostly depend on ramp rate and lift would look into BTR platinum spring kit

also full size chevy imo is more for the older trucks. you would have more luck on performancetrucks.com or gmfullsize.com

shortpump

yeah there shaved 60 thousands (60/1000) or 0.060

shortpump

Is there any way to compensate with head gaskets or something if this is too much milling?

bobfig

only thing i can think of is using bigger head gasket. now idk if you milled to much but i would almost definitely measure the ptv clearance.

from my finding most a head would be milled would be around .040-.045" before you get alignment problems. like mounting the accessory bracket or intake.

milling as much as you did you might not be able to do a high lift cam but get away with a low lift one but you still need to measure.

here is a .066" compressed gasket. stock is .051".
$124 each
http://www.summitracing.com/parts/cg...make/chevrolet

ooo and milling that much off you are in the ballpark of 11:1 compression.

shortpump

The more compression the better though right? if it works... do you have a reccomendation for cam size?

shortpump

With that gasket it would leave me with about .045 milling over stock. Right?

bobfig

theoretically yes. but there is a thing called quench and that may be needed to look at. depending how much the piston is out of the bore the quench may be a little much.

if you have time i would just mock everything up not necessarily torque everything down just enough and check ptv clearance first before you order those gaskets.

shortpump

What is "quench" and what does "ptv" stand for?

Like I said idk much about this stuff

bobfig

ptv = piston to valve

quench is the distance between the piston to the cylinder head.

in ls motors the piston is about .008-.015" poking out of the bore. with the stock head gasket .051" compressed would mean that there is about .043-.036" quench. you really want to aim for .035-.045" of quench if to much you could end up getting detonation, too little you would get mechanical problems like piston hitting valve or head.

thats why even running the .066" head gasket may work but would give you around .058-.051" of quench.

JakeFusion

iTrader: (7)

I'd run a GM .051" MLS gasket, flycut the pistons if you need additional PtV... you'll be in the 11.1:1 with those dished pistons and 52cc heads.

I'd ditch the camshaft. It's terrible for the truck.

Something like the FlowTech Induction StreetSweeper-TQ 220/224 .597"/.592" 111 LSA for the truck. With 11:1 CR... it'll make huge torque. It'll work with the FTI 3000 as well.

Just run a good valvetrain with it - good springs (PAC Racing 1905 or 1207 or Lunati 73925 or BTR Platinums), hardened pushrods (BTR heavy wall 5/16" or Manton 11/32"), BTR trunion upgrade in the rockers, and upgraded lifters (Morel 5315).

shortpump

How does fly cutting the Pistons work? What am I achieving with a 11:1 CR vs 9.5:1 CR? I guess what I'm asking is what exactly does more compression help with.
Your not saying dish the cam all in general and keep the cam stock, but look at the street sweeper cam right?

JakeFusion

iTrader: (7)

Don't keep the stock cam. Run the StreetSweeper.

Additional compression makes more torque everywhere and helps with drivability of a larger cam.

Darth_V8r

iTrader: (4)

Ultimately, the purpose of an engine is to generate torque. Torque = force x lever arm length. In the case of an engine, the stroke is the lever arm length. To create more force, you create more cylinder pressure. Pressure = force x area. So, increased pressure = increased torque. You can increase pressure two ways. You can get more air and fuel in, so when it detonates, you get higher cylinder pressures which makes more power. You can increase the compression ratio, which raises cylinder pressure by compressing the charge into a smaller space. The additional benefit to increased compression is efficiency.

Fly cutting pistons puts these crescent shaped notches in them to create more space between the pistons and valves where they would otherwise collide without making major engine modifications.

You should be OK with 11:1 compression as long as you have access to 93 octane gas. Where I live in AZ, I can only get 91 octane. I have my motor at 10.6:1. If I were to install a larger cam with more overlap, I would mill my heads further, but for my cam, the heads and gasket thicknesses are about right.

Hope all that helps. Trying o give you some of the "why" behind the "what"

shortpump

Thanks, I'm getting the thought of it now. How do I go about flycutting the pistons?

I didn't really want to pull the whole motor out of the truck, just take the front end down enough to get the cam to slide in, i'm guessing fly cutting the pistons would involve pulling all the pistons out and taking to a machine shop?

Darth_V8r

iTrader: (4)

I would pull the Pistons. There are some online ptv calculators you could enter your engine specs to determine if you need to fly cut.

One thing you might want to know is duration, not lift, is responsible for tighter ptv clearances. So, if you calculate ptv clearance issues on the mouth thumper cam, you could reduce the exhaust duration or go with a bit wider LSA, and you'd be fine.

If you're looking for good grunt and a good choppy idle, look into the tick performance Saturday night special torquemax 2. Specs are 227/235 - 110+3. That can gets rave reviews from many users. Shouldn't have any ptv problems with that cam. Will work well with those heads

bobfig

now would you recommend that cam in a extended cab truck?

to me vinci trucker cam would be ba better choice for a truck but i dont know about the ptv clearance. this is assuming that everything bolts together fine.

JakeFusion

iTrader: (7)

I still stand by this. It may clear even with that much milled...

StreetSweeper-TQ 220/224 .597"/.592" 111 LSA

Darth_V8r

iTrader: (4)

For an extended cab truck, jake's recommendation is better. For some reason I was thinking car.

shortpump

You got any kind of idea what kind of HP i can expect out of this on a truck? looks like there showing somewhere around 20 on a GTO