Bad Combo Questions.

[mach1sys]

I am about to put together a bad combo here it goes
302ci
9.8:1 comp ratio
E-cam
vic jr heads untouched
performer rpm manifold
70mmTB 80mmMAF
1 5/8 eq length headers with 2.5 hpipe

You think those heads will keep it from going over 300rwhp? I know they are way too big for a 302 but I dont want to sell them cause I am going to need them later on a future combo. All info would be great, if anyone else is running jrs on a 302/306etc post up how it runs. Thanks!

 

[Nosfurato]

I am about to put together a bad combo here it goes
302ci
9.8:1 comp ratio
E-cam
vic jr heads untouched
performer rpm manifold
70mmTB 80mmMAF
1 5/8 eq length headers with 2.5 hpipe

You think those heads will keep it from going over 300rwhp? I know they are way too big for a 302 but I dont want to sell them cause I am going to need them later on a future combo. All info would be great, if anyone else is running jrs on a 302/306etc post up how it runs. Thanks!

A few things,.. why go with an 80mm MAF when using a 70mm TB??
Think of it this way. Take an imaginary straw, that is suposedly 80mm strait through. blow through it as fast as you can a couple times. nice and uniform right?
Now, pinch that straw a bit. Blow through it again. Its gonna be a bit tougher.

Combination is key.

For 300 Rwhp, I really dont think you will need parts that big. That will kill the air velocity.
Air valume is good, dont get me wrong.. big parts=big valume. BUT, it kills low speed velocity.

HOWEVER.. If you go with that combo, and ditch the shorties for some longtubes. Ditch the E-cam, and goto either FTI or AFM for the cam.. and spin the be-jezuss out of it. 6600 RPM+ I bet you would murder your 300 Rwhp goal.

If this is a track only car, go big.

If this car is to be driven on the street, the E cam will work, but drop the size of the maf, and T-body a notch.

My .02 anyway..

 

[Rick 91GT]

The 80mm Pro-M will not be an issue with the smaller TB, it is one of the best reading meters out. Most class cars limit you to a 80mm MAF and 75mm TB and it works just fine.....

I see no problem with the 300HP with some changes, dump the E cam it's not a good choice and get somethiong more aggressive FTI, AFM, etc... I would suggest 30# inj, 255lph intank pump, long tube would be better up top but you can make the power with the shorties...

 

[5.0 HOtrain]

The 80mm Pro-M will not be an issue with the smaller TB, it is one of the best reading meters out. Most class cars limit you to a 80mm MAF and 75mm TB and it works just fine.....

I see know problem with the 300HP with some changes, dump the E cam it's not a good choice and get somethiong more aggressive FTI, AFM, etc... I would suggest 30# inj, 255lph intank pump, long tube would be better up top but you can make the power with the shorties...

What he said

 

[mach1sys]

The only problem I have with going to a bigger cam is my PV clearance with the 2.05 intake valves on the jr's. I have some 38 injectors matched to the 80mm pro-m. I plan on boosting this motor in the future so hopefully that will clear everything up

 

[Rick 91GT]

I figure with a 9.8:1 compression ratio you had aftermarket pistons that would be made for the large intake valve on the Jr's. What piston (specs) are you running, is the piston "0 deck" or below/above?

 

[thumper460]

buying the parts for future mods is cool!! but with all the mismatched parts , expect some problems!! going to boost in the future... then keep buying and tweeking what you have and dont worry about 300 RWHP now.. or pull the big heads off and go smaller for more flow N/a with the small E cam!! OR as they say... "custom grind!!" a good cam IS the whole engine!! But then the cam might not meet the blower needs!! SOOoo.... as I sugested... worry about the future and for now... just have fun THINKING of the future!! cool??

 

[mach1sys]

I am running TRW pistons with valve reliefs (small ones) the piston sits .003 out of the hole so my my quench distance is around .038 I will just worry about when I get boost, the car tossed a rod so I need to get it back on the road. After a few months it will be boost time. Thanks for all the info guys.