Small Block & Big Block Chevy Specific - timing on a boosted 490bbc

I was just wondering what kind of timming u can run on a 490bbc (n/a) up to 6200rpm. we are at 18psi of boost at 21 deg. (6200) of timming on my 490 engine combo right now, are we safe? on E85
going to dyno this weekend hope to put 1K down to the tires.

the charger is intercooled

Should be fine as long as cooling is proper enough, has alot to do with the cam and efficiency of the heads too. They are aluminum heads right?

the engine is purposly built for boost the cam was custom 595 610 (228 238) 114 (I think) big bad intercooler
the heads are alum. bb2extra 365

Depends on the fuel, the higher the octane the bigger your tuning window is.

The heads are WAY too big for under 500 inches and the cam is too small for the heads, as for N/A timing 34*-40* depending on the what the combo likes and fuel available. I have run as much as 42* total on BBC race mills.....

Those heads are decent at low lift but you have no way to really take advantage of them as they peak in the .750"+ lift range. It will work, but no where near optimal.......

Good luck and report back when its done!



Cubic Inch Compression Camshaft RPM Application
BB-2X 509 - 555 13.1 Minimum Roller 4000-7500 Pro Street/
Drag Race
BB-2 XTRA 540 - 582 13.1 Minimum Roller 4000-7500 Pro Street/
Drag Race
BP BB-2 XTRA 540 - 582 13.1 Minimum Roller 4000-7500 Pro Street/
Drag Race
BB-3 555 - 632 14.0 Minimum Roller 4500-7500 Pro Street/
Drag Race

the timming just crusing highway is 29-32deg. with no boost , this is a almost every weekend steet driver. under 18psi boost its 21deg with a intake air temp of 105 (ON E85 ETHONAL)
The cam was cut for the steet by comp,(hydraulic roller) i told the engine builder i did not want to spen the motor more then 62-6500 so hopfully it will stay toghether longer, can u get a hydraulic to go that big and spen that kinda rpm 7000
I could no pass on the heads got a pretty good deal, i called bodix and talk to a jason he said the heads where way to big also but with boost they would come in just be a little dogging on the low end thats all rightthisis in a truck. thanks for all the advice keep it coming

Oh it should be a runner dont get me wrong, it will just be a little soggy down low. Boost will always help but its best to size everything accordingly, as far as camshaft choice most hyd roller cams max out around 6500 but I have seen a few grinds that pull to 7000 but the lifters tend not to live a long life.

A set of AFR 305's would make such a HUGE difference from the bottom end all the way to redline. Its much more about port velocity over volume when choosing the proper combo but we cant always get it perfect when on a budget.

Give this guy a call or email on the camshaft, he can advise and grind one for you in house. He makes some KILLER power in everything he does that I've seen..... Make sure you let him know MrOverkill refered you, you can also go to norcal1320.com and have a look around :nod:
http://drcamshafts.com/

i would be kinda of scared if u think the 305s would be that much better on low end tourqe, its a hell of a hand full now with the traction problem being in a truck
the boost comes in almost immediately so i really dont feel any sluggish off the line
I gusse we will find out this sunday what it does
I put in a new pro yank 3400conv. this weekend, on the street its feels awsome very excited to see on the track

Yeah it would be night and day, the whole thing is to make the combo as efficient as possible before the power adder. Heads and cam choice being the biggest contributor to that I always try to size them accordingly. I'm interested to see what kind of power it lays down and would like to get a look at the graph once you get it dyno'd......

Report results when its done please......

there will be a new dyno sheet but it might be not this weekend but next.
but i do have one from two weeks ago, the converter we found out did not like all that power we try to put through it, we pulled it out this past weekend and the paint was blistered and a brown color where it mounts to the flex plate, so im pretty sure we toasted it

Make sure to drop the pan and inspect the trans and change the filter as a precaution. I myself like to change the fluid and filter after any trip to the track, and pretty often after some serious street abuse.....

so the track was closedthis weekend it was to cooled
so we decided to go to the dyno to see what the new converter would put down
very happy the with the converter it put down 655 on a mustang dyno unlocked when my old converter wouldnt do that locked
but im still not happy with the over all power, im pushing 17psi of boost the #s cant be right the tranny cooler never got hot and we never smelled any thing funny so im confusied why my # are so low, please any more advice (490cubes) bb2extra heads 365, cam is 238 248 590 609 114 something like that, still looking for the card (O I FORGOT TO MENTION I LOST OIL PRESSURE AFTER THE 4 DYNO PULL 4PSI IS ALL IT COME UP TO AFTER RESTART) absoultly no ticking or rattaling we change gauges and that did not fix it, (problems all around)

cold brain fart

Sounds like its hurt or the pump went away, cut open the filter and see whats going on in there. DONT start it back up! Until you can get the pan off and look at the bearings.....

I'm telling you man the combo is off you will need to rev that bitch well over 7000rpm to make the power your looking for. So smaller heads or a WAAAY bigger camshaft, it needs .700+ lift to make those heads work on a 489" inch deal.

im off tom. so ill take a look, im looking into a new cam thanks

Talk to this man he's one of the VERY BEST!

http://drcamshafts.com/

OOOOOO yes I feel like a 5 year old that just got a new bicycle for christmas
My oil pressure problem was somthing blocking the line to the gauge so even thow we change gauges at the dyno the line was still block
I pulled the dis. and put a prime tool on and got 40 psi on a battery drill going to try more timming see whats up

were going to the track or back to the dyno sunday O hell ya