Willem @ Fuel Injection Concepts

iTrader: (2)

I'm doing this this week, got a comp cam coming in. can someone help me and let me know what gaskets i gotta order misc parts etc.

Also, is valve spring upgrade a must? what will the stock ones rev to? with the cam what can this bottom end (stock) rev to? (8.1)

I got the 46-422-9 XR270HR duration at 0.050 218/224 .510/.510 lift on an 114 LSA. Anyone else running this? I'm wondering if it changes the idle sound at all... in my book a big bloc should eat that "small" of a cam up and it will sound stock but I guess I have no idea.
Any idea of the duration/lift of the stock cam? Must be TINY to explain what we dyno about the same as a 6.0 even after some tuning.
Will the stock lifters be fine? Pushrods?

Any part numbers and what all and else I may need for this job (tips and tricks), we're doing it this week in truck, and im thinking after pulling the radiator/condensor out there hsould be plenty of room to get the bumpstick in and and out. One big question.. are these like the LS motors where the lifters all sorta "stay" up when you pull the cam out or do I gotta pull the intake off ?

MGMC

iTrader: (46)

good info on cam swaps for the ls engines: http://www.ls1howto.com/index.php?article=23
i dont think you are going to notice much with that cam in a big 8.1. lifters will be fine, hardened pushrods are recommended. with a low lift cam like that im sure you will not need new valve springs, but do a search just incase. everything you take off that has a gasket, replace it. its good practice. oh and a new crank bolt since they stretch

ZZebes

iTrader: (10)

The 8.1 is by no means an LS motor the only thing LS on that motor is the bellhousing pattern

Willem @ Fuel Injection Concepts

iTrader: (2)

i think even though its a mild cam i think the stock cam is REALLY small... am I wrong?

fastrt

iTrader: (48)

I would do push rods, springs should be ok, but have see both break at high rpms. I have no clue how high, but should hold 5-5800 on a daily driver. that cam is small!! I would get into a gmpp cat and look up the cam specs. we have one on the parts counter at work and I will look and see.

James B.

iTrader: (1)

You'll need springs. Stock big block springs start floating at 4800 and are worthless above 5000. How high do you really want to go through? Production 8100's are known to break rods if overspun. You really don't want to go over 5500, and getting even that high needs the springs. The intake manifold will have to come off. The oil pan has to come down enough to get the timing cover off, and then you'll need enough room to clean everything enough to get good RTV sealing in the corners of the pan gasket when you put it back together. Pulling the balancer will be fun. You get no choice pulling the radator and condensor, but it's getting enough room to get a puller onto the balancer that's going to be the tricky part. Swapping a cam on a bigblock still in the vehicle will test your patience. If you end up pulling the heads drain each side with the plugs. The water inlet ports are higher than the head gaskets on a Mark-VII bigblock, so pulling the heads without draining it will flood the cylinders. Good luck.

Willem @ Fuel Injection Concepts

iTrader: (2)

i thought that cam with the 510 lift was highest i can go with stock pistons? (Piston to valve clearance.. anyone know how big a cam I can run then?

MGMC

iTrader: (46)

oh, i thought all the genIII were related. i guess there is always a blacksheep

Manic Mechanic

iTrader: (3)

I'll second everything that James B. posted. It is good information.
Also:
Two guys I know of floated the stock springs with an aftermarket cam before 4500.
The lifters don't stay up, like he said the intake has to come off.
.510 is the highest safe lift figure according to Ray at Raylar. Tie Rod (on this site also) ran one bigger with stock pistons for a while but probably was just lucky.
There are several other things that the 8.1 has in common with the LS small block, but nothing that effects this question.
The stock cam is tiny, based on asking others who've done it I think you'll notice the huge increase in power more than a change in idle, manners, etc.

Vernon

TieRod

You can remove the timing cover with out dropping the pan. I ran the same xr270 cam with 1.8 rockers and yes you will need new springs. I gained 30whp and 50wtq with no tuning before the 1.8 rockers. It's a piece of cake, I started a noon and was done in time to go cruising that night.
BTW all the gaskets are reusable!