2003
Location: madison wisconsin
Posts: 4
cam, question guy's
i bought a 91 firebird t-top'sanyway: it's got a 1974 400sbc in itwith intake350-5425 with 2 tbi's from a 350 truck engine adappted to it. they got injector spacor's and every thing like that all ready done. it was a fun car tell it spun a rod bearing. so know i'm rebuilding it. i swapped the 3.73 gears for 4.11.
it got a 700r4 from a gmc 3500 rebuilt with shift kit.
it sopun the bearing about 4 months after the gear and tranny swap so now i'm building the stuffing out of it. here what i need to know should i use the 318*cam or the 328* cam which would be the best choice cause the old 292* cam wasn;'t all that hot.so those are the 2 cam's i was told to choose from. so what would you guy's sugest. so far best run was 13.88@107mph. i'd like to see about 110mph and about 13.6 time zone. already got a 10.2:1 comp ratio.so it will run good on 93octane. the block and lower end is done. i'm at the cam and head's piont now. so 318* or the 328* cam anyhelp would be nice.

 

Those are gross duration numbers which won't tell us a whole lot.

We need to be talking about duration @ 0.050" to get a handle on what the cam will do, ie RPM range and so on. If you have the cam cards for those two cams, post 'em so we can get a look at what you have.

 

ok so i need to get all the other number's from the cam as well.
like: duration lift ect. ok lte me go see what i can find they where in jeg's.

 

I NEED A CAM THAT WILL RUN 1200 ,1500,1700 TO 4,200 4,500 4,700 RPM ZONE. BUT MAKE 475 TO 525 FTLB OF TORQUE 425HP TO 475HP. IS WHAT I AM LOOKING FOR.
THE OLD RATEING'S ARE 375HP AND 425 FTLB TORQUE.

WELL THE SHIFT PIONT'S OF THE 700R4 ARE 1ST TO 2ND AT 4,300 RPM AND 2ND TO 3RD AT 4,100RPM.
SO AND ENGINE THAT PEEKED AT 4,200RPM WOULD BE I DEAL RIGHT.?????????????

 

I'm not familiar with that intake, but if it is a factory unit, it will be designed for low end torque. With a 292 cam and 4.11's, you should be shifting around 6,000. If it is a low rpm intake, it is not a good idea to bolt in a high rpm cam.

What heads do you have? If they are factory 400 heads, they are also designed for moderate rpm.

Presuming intake is low rpm design and you have stock 400 heads, I think a cam around 218 to 222 @ .050" lift would be better than the huge cams you listed. Comp cams HE268 would be one. But even a cam that small would peak at around 5,000 in a 400. So you are going to have to get the TH700 reprogrammed for higher shift points, say around 5,200 - 5,500.

I have a 400 in my 71 with a 222 cam (Crane Energizer), dual plane intake, 750 carb, factory 76cc heads that I mildly ported. Best et came by manually shifting the TH350 at 5,500 rpm.

With the 3.06 gear in the TH700 and 4.11's, traction off the line is probably non existant. If you don't have SFC's in your t-top bird, install them. That would help, along with suspension improvements. A 107 mph and 4.11's should be in the low 13's minimum, optimized, high 12's.

 

THE INTAKE RPM RANG IS 2,500 TO 6,500RPM'SIT HAD DART2 HEAD'S.THIS IS GOING TO BE MORE OF A LITTLE STREET RACER CAR. LOT'S OF TORQUE REAL FAST.SO YOU'D SAY THE 292 WOULD BE FINE,THE 318* OR 328* MAYBE ALITTLE BIG.
I WANT THAT ROUGHJ IDLE. YOU KNOW THE KIND WHERE YOU SWEAR IT'S GOING TO DIE BUT IT'S TURNING 1,200 TO 1,700 RPM'S.I'D STILL LOVE TO RUN THE BIG CAM. SO HOW CAN I RESETUP MY ENGINE FOR THOSE 2 CAM'S.I FIGURE A 2,200RPM STALL,4.11 GEARS. WITH THOSE HP AND FTLB TORQUE FIGURES I THINK IT WILL LAUNCH AND RUN STRONG FROM 0-110 RATHER STRONG COMPUTER SHUT'S IT DOWN AT 117MPH ANYWAY SO TOPEND ISN'T A BIG DEAL HERE.

 

SFC's?????? I'M ASSUMING THESE ARE SUB FRAME CONECTOR'S????? WHERE AND WHO HAS THEM AND FOR HOW MUCH.

 

mikeydragster,

Your approach to engine building is COMPLETELY wrong. (Turn off your CAPS lock, too--it is the equivelent of YELLING at us and I'm sure you don't want to do that.)

You build an engine with specific elapsed time and speed goals in mind. You DON'T build one for a specific ROUGH IDLE

The idle you end up with is ONLY a byproduct of the completed engine, not the purpose of it. The cam you choose is almost the most important thing in the entire process, so you should NEVER make it subject to the rumpity rump you want to hear.

Just go and tell the other folks at the strip how proud you are of the sound of your engine's idle and how it was the focus of your efforts. If someone doesn't clobber you with a pipe wrench they'll laugh you off the track

Call Comp or Crane and tell them exactly what you are hoping to achieve power-wise with the engine. They will give you VERY good advice and you WILL be a happy camper when that Camaro flies down the track faster than you imagined

 

I already STATED my DESIRD ET i wanna be in the 13.8- -13.6 zone.
just scroll up man. and try reading it from further up sir.

 

Tell that to the cam company. But don't ask for one of their cams according to its rumpity rump factor. You'll sound like a rank amateur.

 

Well i know that. i got told them what i want for power. they told me i need either 318* or the 328*. cams would do great for me.

i told them i got a 91 firebird t-tops with 400sbc in it with intake #350-5425 4x2 intake. with 2 tbi's from 350 truck engine's adappted to the intake.a built 700r4 tranny from a 1 tom gmc. and a 4.11 rear end gear.
it had a 292 cam in a mild 400sbc with 375hp and 425ftlb torque. i wanted to increase that to about 425hp to 475hp and 525ftlb to 575ftlb torque. they said with that intake and dart head's i should use either a 318* cam or a 328* cam. and reprgram my shift piont's at a higher RPM. the 3 question's i wanted answerd was 1.which cam ?? 318* or 328*.
2. should i put a 2,200 stall converter???.
3. with it being a t-top car should i put sub frame conector's??.

 

I'm also doing an 87 gta as a mild street rod daily sumer driver. the 91 is more of a friday saterday night hotrod. for when the real toy's come to town.

87 gta=streetrod/daily driver 91=street rod/trackcar.

 

Yes, you must get subframe connectors in there. That is a lot of torque and will definitely twist the body.

 

i told them i got a 91 firebird t-tops with 400sbc in it with intake #350-5425 4x2 intake. with 2 tbi's from 350 truck engine's adappted to the intake 10.2:1pistons.a built 700r4 tranny from a 1 tom gmc. and a 4.11 rear end gear.
it had a 292 cam in a mild 400sbc with 375hp and 425ftlb torque. i wanted to increase that to about 425hp to 475hp and 525ftlb to 575ftlb torque. they said with that intake and dart head's i should use either a 318* cam or a 328* cam. and reprgram my shift piont's at a higher RPM.
with hoosier p295/50D15's in the rear,and 245/60D15'sin the front. upgraded shock spring's,sturt's,and dual sway bar's. with the 4th gen style ram air hood for it .it's a sweet looking car,especailly with that rounded noise cone and shnazzyfiberglassskirtsandgroundeffect's that the 91and92's have now it looks so 4th gen.now it will have the ***** to back up the tough look it's got.
dual exhaust header's with glasspack'sbolted right to the headers.non of this cat back b.s. single pipe dual tip's crap for this car.it also has the dual dump's like the bandit t/a.
the 3 question's i wanted answerd was
1.which cam ?? 318* or 328*.
2. should i put a 2,200 stall converter???.
3. with it being a t-top car should i put sub frame conector's??.

 

My 70 SS w/a 350 ran a 12.90 with Comp Cam's 292 magnum and a single carb and less compression. Maybe you should look at good heads and, your converter selection. I ran a 10" converter with 4.11 gears in a TH350 w/ ported 292 angle plug heads. The same set up w/ Lunati Streetmaster cam (little less duration and a little more lift than the comp 292 mag) and stock 186 heads w/springs to match cam ran a 13.36.

Just look at the LS1's they're running mid 13's or lower with less HP than what you're looking for. You engine combo doesn't lack power, it just either isn't getting to the ground or is wasted on traction problems.