Engine questions

[low98]

I have a 98 gmc C1500 it has a 383 in it.
The engine has a 400 crank, bored .20, and the heads and block were decked.
It is running about 10.1 compression.
Basically a stock cam and everything else is close to stock.

I want to start looking at cams. I also want to put 1.6 roller rockers, different valve covers to acomadate the rockers, and some other stuff.

I am not afraid to do head work to fit the cam, but I don't want to set off the knock sensors.

Can yal help me out? Give me some info on what to look for or at.

 

[Hogg]

If you dont want to set of theknock sensors, stay away from 1.6:1 full roller rockers. Fulll RR's are noisy and the knock sensors will report the noise as engine knock to the PCM. If you dont modify the tune, the PCM will start pulling timing thus reducing power.
The GEN 3/4 engines use rockers that use a roller fulcrum and solid trunnion, tehse are quieter than teh full rollers that were only used for 1 single year by GM in any SBC, the 1996 got the full RR's and they had 2 recalls on them.
the 4.3's after 2001 IIRC also swapped to the GEN 3 style rockers, that might be a possibilty as well, butI'm not sure how they attach to the head.


If you get a cam grind that allready has teh proper amount of lift you desire right off the bat 1.6:1 ratios arent needed. 1/6:1 rockers are a popular upgrade as they will net you a few hp for those guys who dont want to swap out cams.

there are many many cams to choose from, but if you dont want to do any PCM tuning I cant suggest a cams wap in good conscience.

GM Hotcam is a good mild cam and has netted 330+rwh or about 400hp at the crank with ported (home ported) L31 heads with the stock intake manifold and poppets with PCM tuning.

Any cam with over 0.480" lift withh require either machining to gain some retainer to valve seal clearance OR you can grab some 26915/26918 Beehive springs and COmp Cams 787-16 retainers stock locks for roughly 0.530" lift, you can get 0.050" locks for a bit more lift as well.

peace
Hog

 

[FastOrange]

I have a set of Scorpion Full Roller 1.5 Self-aligning rockers on my truck, VERY quiet and no extra noise, also fit under STOCK valve covers.

 

[low98]

Well thank you for the advice on the rrockers
Actually I am tuning my truck got the scan cable from blackbear today actually

I can get a good deal on machining from the guy who did my engine.
What would I need to get him to do? And are you using this cam?

I want to replace my valve covers to spruce my engine bay up a lil any ways
but thank you.

Any more suggetions are welcome.
Trying to get as much out of the stock intake as possible.
Before I go with a marine or ramjet intake

 

[DRAGGIN95]

Also stay away from a timing chain to gear drive conversion, even the ones marked quiet will give you trouble with your knock sensor.

 

[FastOrange]

Also stay away from a timing chain to gear drive conversion, even the ones marked quiet will give you trouble with your knock sensor.

a typical double roller is the best way to go.

 

[Aloicious]

a typical double roller is the best way to go.

I agree that a timing gear set is a bad idea. but do not use a double roller on a 96+, there are clearance issues with the cranshaft reluctor wheel.
there is a high quality cloyes single roller timing set for the L31 which is very solid and is what I have been using very sucessfully for the last couple years, it should handle anything the OP would throw at it without a problem.

on another note, I've been running comp pro-magnum 1.5 full rollers on my L31 without having any knock sensor issues. I don't know if chaning the geometry to 1.6's would change that or not. if I were you I wouldn't worry about going with 1.6's at all, if you're already chaning cams, just get a cam speced like you want, and run the 1.5's, then you wont have to worry about pushrod hole clearance issues and such.

 

[low98]

Well does anyone have any experience with hotcam?

Would it work ok with my 383? The specs on it are on the original
post.

 

[FastOrange]

I agree that a timing gear set is a bad idea. but do not use a double roller on a 96+, there are clearance issues with the cranshaft reluctor wheel.
there is a high quality cloyes single roller timing set for the L31 which is very solid and is what I have been using very sucessfully for the last couple years, it should handle anything the OP would throw at it without a problem.

on another note, I've been running comp pro-magnum 1.5 full rollers on my L31 without having any knock sensor issues. I don't know if chaning the geometry to 1.6's would change that or not. if I were you I wouldn't worry about going with 1.6's at all, if you're already chaning cams, just get a cam speced like you want, and run the 1.5's, then you wont have to worry about pushrod hole clearance issues and such.

Oh shoot, your right, i forgot about the wheel, yea single roller is way to go in this case.

 

[FastOrange]

I agree that a timing gear set is a bad idea. but do not use a double roller on a 96+, there are clearance issues with the cranshaft reluctor wheel.
there is a high quality cloyes single roller timing set for the L31 which is very solid and is what I have been using very sucessfully for the last couple years, it should handle anything the OP would throw at it without a problem.

on another note, I've been running comp pro-magnum 1.5 full rollers on my L31 without having any knock sensor issues. I don't know if chaning the geometry to 1.6's would change that or not. if I were you I wouldn't worry about going with 1.6's at all, if you're already chaning cams, just get a cam speced like you want, and run the 1.5's, then you wont have to worry about pushrod hole clearance issues and such.

and i agree on the cam and 1.6 deal, i would just go bigger on the cam and stick to 1.5's, when you go to 1.6's you start changing things.