360 build recommendations please...

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danmc77 said:
I'm not against 3.91's, but this car won't see any track time so I would like it to be somewhat comfortable to drive. I'm just a little weary of 3.91's and a 3800 stall for the street. If low 12's aren't within reach using this block and rotating assembly, that's what I'm trying to find out. I would like a nice comprimise of acceptable street manners and low 12 ETs.

I know it sounds like I have no clue, but I've rebuilt several engines and have a passion for working on cars. The thing is, I've never tracked a car so I'm not really sure what a 12 sec car feels like. I have no clue how fast any of my cars have actually run. I've never driven a high stall converter or 4.10's. I just don't want to invest $ into something that I can't drive to a local show or around town.
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You can drive it everyday. Its the stall conv, more than the 3.91 gears that get to you. You only notice the 3.91's at highway speeds 70+ and your mileage won't be so good.

I have 3.91's with a 1800 conv. Its nice, 40-45 mph its nice and happy, stops better too. Sometimes I wished I did go with 4.10's but only because it would have pulled better in 3rd. Rarely do I run out of motor...@ 6000 rpms and a 27" tire its going around 115 mph.

PS...thats why it the old days people would get 7000+ rpms on their 340 motor.

BTW...theres a old saying too..RPM= ruins peoples motors.
 
I'd say build it to drive, and see what it runs. You might be surprised. Not every 12 second car really runs 12s...lol A decent street car runs 13s. A fast one runs low 13s high 12s. Low 12s takes a lot of power, very little weight, or less streetability in a stock stroke small block. If you've never driven one, mid 12s wil probably scare you at first on street radial tires. The 904 will be fine. I dont like stalls higher than 2500 on primarilly street cars. They ruin drivability, they piss away fuel, and they make a lot of noise for not much pull, unless you floor it. You want a stall speed at or lower than the typical high gear cruising rpm. In 3.91s w/stock rubber's case, thats about 2500 at 60. with most convertors, cruising at 45mph in 3rd, with a 3800 convertor and street gearing, will feel like a wet sponge, and every hill or time you try to pull away, it will feel sluggish. And yes, I have lots of experience with Dynamic's "tight 9 1/2" convertors. Tehy are head and shoulders better, but still not what I would want for a car that hits the track a few times a year. Always go more gear, less stall, for a car you want to drive.
 
BTW - should I just use a spreadbore adapter for the RPM intake with the TQ or is there a performance intake that somebody can recommend that accepts a spreadbore carb?
 
Theres nothing made new to accept the T-Q except the Edelbrock Performer and the MoPar M-1 single plane. You will want to do a height check for clearance on the M-1. They do fit under some stock hood.

The adapter on the RPM is doable, but remember, it'll add the thickness of the adapter plus a gasket. This particluar set up I try and it would not fit under my '73 Cudas stock twin scoop hood. You MAY have clearance. I don't know.

Adam might know.
 
Thanks, I guess I'll just have to try it to see if it fits. Do you guys know if the adapter affects performance - meaning would I be better off going with a performer or a stock iron speadbore intake if the adapter will just reduce performance to that level anyway?
 
If you want to run a TQ you can either use a stock 340/360 intake (71 or 72 is best) or get an LD340 and open it up for a spreadbore. They may be others you can use.

A regular Performer may even work ok if you port match it.
 
danmc77 said:
Thanks, I guess I'll just have to try it to see if it fits. Do you guys know if the adapter affects performance - meaning would I be better off going with a performer or a stock iron speadbore intake if the adapter will just reduce performance to that level anyway?
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Its not reccomended to run an adaptor-especially on a high performance application,your better off with the correct intake.
 
Has anybody try to hog out a RPM intake to fit a TQ, a good shop could weld metal to the intake if needed.

A old Holley Street Dominator takes both a Reg.Holley and a TQ, but its a single plane--but not a racing intake, thats the Strip Dominator
 
Just got a 360 off the dyno.

KB107's, J heads with 1.94 valves, XE268H, LD340, Holley 950 (just for the dyno run)

Made 348hp and 395tq with a very flat torque curve. Pretty basic straight forward build. The heads are the biggest bottleneck to making HP. TQ will likely pick up when the 750 holley goes on it.
 
crackedback said:
I have an LD340 already cut for a TQ... I'd cut it loose for $150+ shipping
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How did I miss this? I just bought one.:angry6: Although I got it for $130something shipped, I have to do the mods to it myself. Oh well, I enjoy doing that crap anyway - experience gained first hand.

Thanks anyway for the offer.
 
danmc77 said:
How did I miss this? I just bought one.:angry6: Although I got it for $130something shipped, I have to do the mods to it myself. Oh well, I enjoy doing that crap anyway - experience gained first hand.

Thanks anyway for the offer.
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If you want to swap, I'd rather have a std flange one.
 
These should help you.

bulletin34,p22,carb.jpg


bulletin34,p21,carb.jpg


bulletin34,p08,carb.jpg
 
AdamR said:
I hope my 360 runs as good.
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Adam, the head as choked off at about 215cfm. Put some heads that flow in the 235-240 range and it would likely be in the high 3's, 380-395 is my guess.

It's really a basic build and will have a 2500 stall, 904 and 3.23's with a short tire. We're guessing, hooking up and tuned right it should run really low 13's in the 104 range.
 
Are there any leaking issues in general with this type of mod? It looks like there is very little meat on the mounting pad around the secondaries.

I'm seriously considering swapping with you Cracked, but I don't have the intake yet. Once it's delivered, I'll take a look at it and consider if I want to do the work myself. I'll PM you in about a week once I get it. Thanks for the side-by-side pic. Any opinion on machining the divider? I see yours isn't modified. Is it a worth-while mod for a street car looking to dip into 12's?
 
Milling the divider get you upper rpm and slightly better fuel distribution at the sacrifice of lower end torque/power.

Let me know. No problem if you don't swap. Just hate to see another unmolested LD go to the big intake manifold in the sky... :sad10::grin:
 
That milling of the divider trick is a race mod that MoPar suggests to use with the large cams of the day. You may not want to do that if your cam is smallish. Under 240* @ .050.

You can get a preety stout street cam under that duration with loads of lift and power making potential. Cracked backs build shows just that and his cam, the Comp XE268, is still on the smallish side, excellent for the street. Once his heads get bowl ported up and the flow kicks up to the flow mentioned he's looking for, the power will really pick up well.
 
Hey guys, I just remembered that I have a new Performer RPM cam and lifters that I bought several years ago and never used. 4.88/.510 lift 234/244 duration @ .050.

If I run that cam with the LD340 opened up for the TQ, port match intake and exhaust, hooker comp headers, 2 1/2 dual out the back and try to bump up compression to 10.0-1 with a thinner gasket, and 4.10's in the rear- does that sound like a combo that would push me in the 12's? I know there are more variables, but I don't have everything worked out quite yet. Going to go with street tires, but try to find the stickiest for the street at about 27" tall. Oh, I have to find out more about porting the heads, but I'll pocket port and smooth them up as well. What do you think?
 
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