Hey all I am building my 305 TPI convertible for the winter and looking to wake up the 305. (I already have a 350 car this is my daily driver) I have the zz4 heads coming I don't know what cam I want. I am going to use SLP runners and a 52 mm Throttle body. I already have the LT4 cam so I already have the 1.6 rockers on the car. This is a MAS Car

Hot Cam w/1.6
218/228 .525/.525

ZZ4 w/1.6
208/221 .504/.540


Thanks
Brian Felts

 

What do you do differently for a winter engine?

 

Keep it warm and cozy until the **** comes back I wrote that wrong sorry!! Its my winter project. I have my RS 355 done and need something to keep my hands busy. I have driven a lot of cars and I can't think of one at $30,000 or less that I enjoy more than this rag top.



Brian Felts

 

Keep the LT-4 cam. Port the ZZ-4 heads and shave them to get a true 10.3:1 compression on your 305
with the aluminum heads.

Do headers and big exhaust. Change the rear gear.

 

I have the full exhaust and 3:23 posi from a 99 T/A. I drive the car every day so I don't want to go too far with the gears.



Thanks
Brian Felts

 

i'd say of the two you're better off with the hotcam since the heads on the zz4 flow good on the exhuast side naturally. i'd stick personally with the LT4 cam for a daily driver though over the two selected and work on other area's of the engine/drivetrain. that's alot of cam for a small bore engine to pull off and be a comfortable daily driver.

 

Don't be a woose : when you cam up a motor it is no longer efficient at low rpm.


A larger cam with more duration than the stock TPI cam will shift the torque up into a higher rpm range. (even a LT4 cam) Thats how it makes for more horsepower. Low rpm torque is reduced.


Trying to cruise at 1400rpm will not work in a cammed motor.

Some 3.73's or 4.10's will match the power band of your modded 305 with a larger LT4 cam and big runner intake
and still cruise nicely in overdrive or 5th.

Don't even think about a Hot cam unless you're going to run 4.10's behind a 305. The bottom end torque will not be there.

No it will not be reving too high. Overdrive or 5th (man)
reduces the effective gear ratio by 30%.

Luggin a cammed motor at low rpm with a low # gear will not save fuel.

If you have an automatic you'd want to get a higher stall lockup converter too.

A 3.73 or 4.10 is right for your car.

How tall are your rear tires?

If you want a low rpm cruiser (3.23gears)use The roller cam out of a
350 RAMJET crate motor with your 1.6 rockers.

196-207@.050 .431-.451" @1.5:1

.460-.481" @1.6:1

lots of lift and short duration.
This cam has lots of low end snap but makes good power.

Thats what you want for a cruiser.

Mildly port the new heads, Shave 'em to get the true compression ratio up.

Its all a matter of details and quardinating the combination.

Big cam= higher rpm ...needs more rear gear, compression and head flow. Or you'll just have a slug that doesn't do anything well. Especialy in a small(er) motor like a 305. Very easy to over cam it.

 

Tires are 245/50 and its got a 2000 stall B&M converter in it. I like the lt4 cam. I was just looking for a little more out of the mouse. My 350 with the hot Cam and Vortec heads idles at 1000 rpm and cruises nicely at 1000 to 1500 rpm.


Brian

 

Use the RAMJET cam in your 305. Put some gear in your other car and it might actually be fast.
A hot cam needs gear. It's not a diesel motor.

 

Well it depends on your idea of fast. I have beaten many 302 mustangs just like it sets. LOL However the RAM JET cam is smaller than the LT4 that is in it now. However when you figure in the 1.6 rollers the LT4 calls for they are just about the same.

Ram Jet
196/206 .431/.451

LT4
208/210 .476/.480

 

yes the ramjet cam has less .050" duration.
But it has higher lift and more lift curve above .100" lift

with 1.6:1 rockers it has tons of lift.
This cam makes more torque and HP in a RAMJET Motor
tha a LT4 cam makes in a LT4

If you want to "wake up your 305 that has a 2000stall converter and 3.23's this is a good cam for it.

If the Lt4 cam was so good in your 305 you would not be posting looking to "wake it up"

Mustangs are easy to beat. If you do it right you'll be smoking more than your share with the 305 car.

 

I see however the specs that GM is giving has the LT4 below the Ram Jet however the LT4 was under rated by big numbers. It ran with the LT5 (zr1) in everyting but top end MPH.

I got the Ram jet lift in at (with 1.6 rockers) .461/.481 next to the lt4 .474/.480 where am I missing the higher lift.


Brian

 

thats a ton of lift for a short duration cam, which is what you need. The difference between .460" and .474" lift for the very short time its at full lift is nill.
The duration and midlift curve have much more effect on the power band.

Put it in the motor, do the other (porting, compression) mods I suggested and you'll see.

Cam the motor for torque, let the ported heads make the HP.

Nothing "wakes up" a car like some rear gear. I'd even consider some 3.73's with the ramjet cam.

Seat of the pants, set you in the seat usable torque is what you're looking for when you want to "wake up" a small motored car.
The ramjet cam is a powerfull new design, don't be fooled by the numbers.

A stock lt-4 will not run even close to a ZR1.

330 Net hp vs 375+ net hp

 

i would however run a bit more stall. that's one thing that wouldn't effect much on the cruising side, but would make it much quicker at lower speeds. with the heads you're running on that engine, you can't gain much more i'd think by recamming it with drivabliity in mind.

 

..see this post then look up the cam specs at Comp Cams