Have I made the right choices?

-
X

Xstream_1

Well-Known Member
Joined
Jan 19, 2005
Messages
257
Reaction score
1
Location
South Boston,VA
I have just finished putting together the 318 for my 68 fastback ( my very first engine build ). I have 30 over flat top pistons, Edelbrock RPM Performer heads w/ 2.02/1.60 valves,stock crank and rods, Comp Cams 270H, 270 dur. 470 lift, 1.6 roller rockers, aluminum dual plane intake, TTI headers, 600 cfm Holley, I have a 8.75 rear geared 3.55, and 904 trans with a 2800 stall. I am curious as to whether I have made the right choices for a street machine that will see limited track use. Thanks in advance.
Garland
 
Your only mistake I see that you made is the heads.These heads would be better off on a 340&360,not a 318.A 318 needs a smaller valve to keep the volocity up and having a 170cc runner will kill bottom end and mid range,but the rpm,s above 5500-8000 will be really good.Problem is,you will never go beyond 6500.I would use a smaller cast iron head,port matched and bowl blended,and save the eddy,s for a 360 motor.The parts you have will work well,if you go with a smaller valve head.What you have done is brought a fire hose to water the garden,when all you need is a garden hose,Mrmopartech
 
That's a lot of cam for a 318, especially with 1.6 rocker arms. What did your compression ratio work out to? You need at least 10:1 with those aluminum heads. You may also want to consider 3.91 gears and a 3200 stall convertor to help overcome the soft bottom end.
 
Your 1.6 rockers is going to give you a extra .032 inches of lift,brought up to .502,it will also make your motor think its got more duration as well as the quicker opening rockers will cause this.Also remember that what ever your C/R is with iron heads,you will loose 1 full piont to alley heads in the thermal heat lose?So if you had 10.0/1 with iron heads,its now 9/1.This is why the cambers are so small,Mrmopartech
 
Wow! Thanks guys , you've given me a lot to think about. The heads shouldn't be a problem to change as I haven't finished prepping the engine compartment yet.
Thanks Again!!!!!!!
 
I tend to agree with the other guys here. With the combination of the big valve Eddie heads, 1.6 Rockers, the Comp 270 cam, and the 3:55 gears, you won't have squat on the bottom end. Once you get to about 3500 to 4000 RPM, it should pull like a tractor, but below that it will probably be a real dog. From traffic light to traffic light you probably won't win many races. As Mrmopartech mentioned, this would be a killer combo for a 340 or 360.
 
Xstream_1 said:
I have just finished putting together the 318 for my 68 fastback ( my very first engine build ). I have 30 over flat top pistons, Edelbrock RPM Performer heads w/ 2.02/1.60 valves,stock crank and rods, Comp Cams 270H, 270 dur. 470 lift, 1.6 roller rockers, aluminum dual plane intake, TTI headers, 600 cfm Holley, I have a 8.75 rear geared 3.55, and 904 trans with a 2800 stall. I am curious as to whether I have made the right choices for a street machine that will see limited track use. Thanks in advance.
Garland
Click to expand...


Here's some food for thought? I/We have a 318 std bore and parts, 9973 heads which are 318's from 75-76 engine we use a .509 comp cams cam and adjustable rockers, to get the most out of the cam. Then the heads are gasket matched and bowl blended, we also used a M-1 intake and 1 5/8 hedders with a 750 vacume secondary carb with mods to the fuel metering. We have the total timing set at 30*, with a modified stock distributor. The engine runs on 87 octane gas with out any problems the actual compression ratio is 8.9:1 the little engine makes 440HP peak @6000 and 357 HP to the ground, the torque is 427 @ 4500 peak and 327 to the ground the 1970 duster ran 12.20s spinning through low gear only due to the stock suspension, with M/T ET streets, the car hits the scales at 3100 and change with the driver. We are looking for mid 11s when we get traction and tuning corrected.
We have tried the bigger heads/valves route only to be dissapointed, so we backed it up and the little engine responded instantly. We used the 1.78 318 intake valve and used a 1.60 exhaust valve from a 360 head. The head cced @ 132 on the intake and the exh. @ 52ccs, the chambers are 64 ccs. The int. flowed 213 cfms and the exh. flowed 190 cfms. The hedders are 38" street type dyno-max.
I hope this gives you some more insight.


BJR Racing
 
You said limited track use.!!!

I like your combo more for the track. I know I could have a lot of fun with that.

But personally, I think that stall would drive me nuts after a while with all the cruising and city driving I do.

Jim

DSC09537.JPG
 
Sorry, I'm misunderstood, I was just using this as a reference, I'm not telling him to do this, I'm just showing him that he can make some real good power without having to do alot of stuff to his engine.
Now IMO I would keep the short block and put the small heads on from a 318 along with a 750 cfm carb 3310, because the secondaries are vacume operated. This way he can run on a 2bbl when street driving and have the option of a 4bbl when needed, or when the engine needs it. I use to run a 600 holley and went to a 750 and the gas mileage didn't change but the power did, and the engine became more driveable. Keep in mind that a 750 vacume carb when on the primary 2bbls is only 325cfms as rated, being that they are the same size front and rear venturies. Most 318s came with a 300cfm carb or there abouts, this was the small 2bbl and the large one has about 350cfms.
This is what I would do but once again this is just my opinion. With the engine done this way I was getting 15-16mpg in a P/U truck with a 3.08 gear.


BJR Racing
 
NiceFishEh said:
But personally, I think that stall would drive me nuts after a while with all the cruising and city driving I do.
Click to expand...
I have a 3200rpm stall in my daily driver (ImpalaSS) and I love it. My 16yo son was mumbling something about whiplash last weekend. :wink:
 
OldVart said:
BJR Racing:
Welcome aboard. :)
Click to expand...


Thanks! Glad to be here. A good friend of mine told me about this site and I figured I'd try it out for awhile.

THANKS! MRMOPARTECH
 
Hey OldVart:

BJR lost me in all that tech, but by the tone of his post , he really seems to know his stuff. I'm not about to question that combo.

As for xStream 1, he's got some nice goodies in that 318 as well, again, a nice sounding combo.

My comment was more directed towards the stall. I welcome the whiplash factor, but around here, it's just an excuse to get pulled over every time you squack the tires. I just think I would have more fun with a stall at the track.

Jim

DSC09533.JPG
 
Now I got ya Jim! I'm about the same trying to decide on what TQ to use this time. I need to go higher than stock, but don't want to get carried away with too much stall with only a 3:23 in the 8 3/4. I'm kind of leaning toward something in the 2400-2600 range, but want to stay at least 500 RPM below my highway cruise RPM. And I know exactly what you mean about barking the tires. I live out in ranch country, but when I go to Edmonton or Calgary I really have to watch mayself. Being picked up by the fuzz is REALLY painful. :)
 
Hey Sid:

I just rebuilt my 904 this summer and installed a new stock torque converter. The rest of the car is stock, and would like to keep it this way. This is the first auto I've ever owned in a muscle car.

The four speed is still my first preference for the street, but I think it's hard to beat a done up auto with the right stall on the track.

BTW your '66 seems to be coming along pretty good. Those done up Valiants can look real cool especially when you hide unsuspected goodies under the hood.

Jim

DSC09536 (Custom).JPG
 
Jim:
I agree with you on keeping that fish of yours stock. I've had a 727 in mine for the past 15 or 16 years, but this time I'm going back to my original 904 tranny, with a rebuild, TF2 shift kit, and ?? converter. :) I didn't get much work time on the Valiant this summer, although I got the rottisserie finished and working. Seems I spent most of the summer cutting 4 acres of grass between the constant rain storms, then spent 3 (SOBER) weeks in NFLD in July/Aug. If we get a decent fall I'll hopefully get some more done.
 
Xstream_1 said:
I have just finished putting together the 318 for my 68 fastback ( my very first engine build ). I have 30 over flat top pistons, Edelbrock RPM Performer heads w/ 2.02/1.60 valves,stock crank and rods, Comp Cams 270H, 270 dur. 470 lift, 1.6 roller rockers, aluminum dual plane intake, TTI headers, 600 cfm Holley, I have a 8.75 rear geared 3.55, and 904 trans with a 2800 stall. I am curious as to whether I have made the right choices for a street machine that will see limited track use. Thanks in advance.
Garland
Click to expand...
I think it'll work nice. I agree IMO if it were my build, it would be a ported 318 head w/ 360 valves. But the 2.02's aren't the end of the world.
Whats the comp. ratio?
Also, I do not think the cam to be to big even with 1.6 rockers.
Math; 470/ 1.5 = 313.3333 X 1.6 = .501.3333333 etc.....
This makes the cam more aggressive. Not so much as bigger. The opening and closing events are the same but with more area under curve.
 
I have no idea what the compression ratio is! I can tell you that the bottom end is stock ( I don't think the block has been decked ) except I had it bored 30 over. I believe the heads had 63cc chambers. I purchased the heads because I felt I got a good deal on them ( less than 900.00 ). I had to take the advice of a bunch of GM fans due to the fact that we don't have but a couple of Mopar guys around. Oh yea I almost forgot I used 285n sealed power pistons with 4 valve reliefs. THANK YOU GUYS FOR ALL THE INPUT!
 
Can anybody find out what the deal is with those pistons? Web sites? Specs?
One more questio for you Xstream, what head gasket did you use?

The advice of a GM fan could be bad. If the GM fan is not a bull headed chevy freak and honestly trying to help and, most importantly in addition, a honest engine kind of guy willing to look into stuff, it shouldn't be a bad thing.
He may not know the in's and out's of MoPar engines, but if hes a good fella.......
 
Rumblefish,
I used Fel-Pro 1008 head gaskets. I think they were 4.180 bore and the thickness was .039. As far as the advice I have recieved I don't think that he would mislead me on purpose, after all he's originally from LI also as is my wife and her family.
Thanks
Garland
 
IMO That combo is poor. The velocity will be bad and it will not run hard. Loose those heads for the smaller ones, Those TTI's are pretty big too? Keep those heads for another combo.

VELOCITY IS KING!!
 
Interesting numbers BJR, and welcome...
X, you have soem good parts, but like it's been pointed out, it may ba little soft down low. What is the calculated compression ratio? If the static ratio is lower than 10.5:1, it's going to be soft. If the engine has good pistons, and a tight quench, I would have wanted to run around 11:1 compression to keep it snappy with the aluminum heads..
 
You must log in or register to reply here.
-

Back
Top