360 Budget Ideas?

[kb67mopar]

I picked up a low mile rebuilt 360 for a really good price and need some professional input. I have an edelbrock performer dual plane, holley 750 vac secondary carb already. What should I do with the heads, cam and ignition are my questions?

My goal is somewhere around 350 hp, I'd like to run power brakes but still have some aggressive idle, and spend as little as humanly possibly (budget is very low) And I'll also be using some sort of header as well.

I have two sets of heads a set of "915" casting J heads with the 1.88 valves or a newer '85 (forget the casting) heads which are on the engine but I believe are pretty much the same. Are these worth porting or is there an economical option?

What is a decent electronic ignition on a budget that will work well and be reliable?

And the toughest one, what Cam?

 

[70rr-brian]

Well for starters that 750 is probably too much for your goal. So if you don't have about a 600cfm laying around there will probably be that additional costs.

Do you intend to leave the bottom end of the motor as is? Because the machine work alone on the heads and block might cost more than you want to spend. Might want to talk to a machine shop to find out how much that is going to run before you get too far into all the particulars. But I don't know what you budget is.

Getting 1hp per cube is pretty easy these days. But really depends on what your budget looks like.

 

[Cranky]

What do you have for tools etc? The more you can do yourself, the cheaper it is to go fast. Doing some port work to the valve pockets really wakes them up. The factory back cut in that area really sucks and just doing that and then blending the work up into the port works well on stock engines even. Also, matching the port entry from the intake helps too. If the head port entry is larger than the intake, that's not so bad but if the head's entry is smaller than the intake, that hurts. Kinda like tripping up a flight of stairs....it's hard to do. You end up just falling down and stopping but going down is really easy.

 

[oxytousc]

You can have a mopar electronic ignition new for less than $200. It should be plenty of spark for what you want.

 

[duke51]

I have a 1975 360 in my coronet. It has a 1968 340 very mild stock cam, 340 X heads with adjustable rockers, Hooker comp headers, Edelbrock LD 340 intake, 750 Holley double pumper, 2500 stal TCI converter, TCI street and strip trans, and 3:23 gears. 750 is NOT too much for this engine. I had an edelbrock 600 on it and the 750 makes way more power. And when I drive it sensibly, I get 15 MPG. Also have Mopar electronic ignition and chrome box and accell SS coil.

 

[oxytousc]

Why the double pumper? I'd think you'd be doing better with a vac secondary carb. As I understand it, double pumpers are best for track cars or very light cars, but a 4150 style carb is the way to go for the street on our cars.

Also, I have to agree with 70-rrbrian, 750 is too much carb. I am building a 408 and I barely need 750. I would think that you could be getting 17-18+ mpg with the right carb and that gear setup.

 

[duke51]

Everyone is entitled to their opinion. I know what works on my cars. Been running Mopars for 43 years. Had a 780 on it and it ran good but runs better with the DP. The 780 is for sale for 150 plus shipping.

 

[duke51]

By the way, a 750 DP is a 4150.

 

[kb67mopar]

Why the double pumper? I'd think you'd be doing better with a vac secondary carb. As I understand it, double pumpers are best for track cars or very light cars, but a 4150 style carb is the way to go for the street on our cars.

Also, I have to agree with 70-rrbrian, 750 is too much carb. I am building a 408 and I barely need 750. I would think that you could be getting 17-18+ mpg with the right carb and that gear setup.

I don't know if I agree that it is too much carb, I think if jet correctly it should be ok. I am going to run it and see since I am not in a position to buy a new one.

As far as budget goes I want to spend as little as possible, not really a budget set aside. I just want to put together an economical package and figure out my spending as I figure out my plan. I may run it as is for a while just to get going, but for now the body work and trans are the priorities. I just want to get this figured out.

I agree on the mopar ignition, I think ill be going that route too. For heads I can do some port work I just wanted the opinion as to if they were worth porting.

 

[DesertBilly]

Ditch the vac secondary.... Dp is the only way to go and on our 408 stroker we ran a 780dp and the car loved it 750 should work out good for you if u plan on openin it up like u say u are

 

[rumblefish360]

750 is NOT to much for a 360 is stock form even from the smog years. Been there done that these guys do not know what there talking about. Jet it correctly and it'll be fine.

325 HP is an easy number to reach. I'm just wondering if it is at the flywheel or rear wheels you want 325 hp.

For a flywheel hp of 325, use stock everything except headers and the MP replacement 340 cam. NOT the OE 340 cam. (It's a broom stick) The replacement cam is ground on a 110 centerline for that muscle car sound. Install it 2* less for more chop at idle.

The MP chrome box is worth it for the ignition as well as the MP distributor. It's actually a good piece.
Leave the heads alone. Add 2.02's at most. Though there not really needed or used well until higher RPM ranges. No need to port the heads. If anything, just a real good valve job on a multi angle cut. Back cutting valves helps low end lift.

The heads would be worth porting. It is (Or should certainly be) cheaper than getting new heads. But the heads will only port out so much, which is far beyond 325 HP. There should be no problem in getting an honest 500 HP out of stock heads.

When you look into headers, Hooker makes a set for your car that doesn't have the normal cursing and screaming 1 size fits all style with the 3 drivers side tubes going under the front end linkage.

In my 73 Cuda, I have Hooker Super Comp headers @ 1-3/4 inch. This size is still good for your goal without a sacrifice of low end torque at any measurable (Or seat of the pants) loss of torque.


UN painted units from Summit racing.com; http://www.summitracing.com/parts/HOK-5115HKR/


Here's the page from Holley/Hooker.com; http://holley.com/5115-1HKR.asp

 

[kb67mopar]

Im thinking rear wheel sounds good, though I am not worried either way, its a street car that I may eventually take to a strip just for kicks.

I think I am going to port match the intake and heads when I put new gaskets and seals in it. but beyond that probably leave them stock.

do you have the part number for the 340 cam? I am not too knowledgeable yet with duration, centerline and how they effect the engine.

 

[Meep-Meep]

The 360 4 BBL has a pretty good intake stock (similar to the old 340 high rise) and is well up to the task for a good street performer. I would sell the 750 carb and intake and use the money to fund other items that will give you more bang for the buck performance. A good cam selection with otherwise stock heads and intake can make a really big difference. Also a proper advance and fuel curves are probably more important yet.

Free up the exhaust. Maybe even add an inexpensive set of headers.
Get a cam designed to work with low compression.
Optimize the advance curve.
Factory intake with EGR disabled. Should be almost free at a swap meet, unless you already have it.
Factory TQ carb rebuilt and working properly. The key word is PROPERLY.

Focusing on getting the most cylinder pressure for the fuel used will yield a responsive engine and lots of driving enjoyment.

 

[rumblefish360]

Im thinking rear wheel sounds good, though I am not worried either way, its a street car that I may eventually take to a strip just for kicks.

I think I am going to port match the intake and heads when I put new gaskets and seals in it. but beyond that probably leave them stock.

do you have the part number for the 340 cam? I am not too knowledgeable yet with duration, centerline and how they effect the engine.

The replacement cam.
http://www.jegs.com/i/Mopar-Performance/312/P4452761AC/10002/-1?parentProductId=746961

You'll need a lot more engine to make 350 at the rear wheels. The trans and drive train will eat a lot of power. Figure on 20% more engine power to make that 350 at the rear wheels. (Just to be sure)

This makes the engine at the crank about 430 HP engine. This will certainly require new pistons, 2.02 ported heads and a different manifold (RPM) and cam. (Like this one or equal: http://www.jegs.com/i/Mopar-Performance/312/P4120231AC/10002/-1?parentProductId=746961 )

I would still spend the coin on the Hooker Super Comp headers. The regular headers from any manufacturer will have 3 tubes going under the front end steering linkages and for surely scraping the ground, denting the headers closing up the tubes, curtailing performance and then rusting out making a lot of noise. This will then require replacement headers at another $100+ dollars.

Save yourself the head ache and get the Hookers or tti headers. There worth the price in the long run. And A LOT easier to install!

 

[kb67mopar]

yeah I will settle for whatever I can get out of a slightly ported heads, a cam swap, stock bottom end, and headers. I am not drag racing, so its not imperative, one day I will rebuild the thing the way I'd love to but for now I think I will have to settle.

Thanks for the ideas so far.

 

[rumblefish360]

What gear ratio do you have or are going to use?
Is a converter change out?
Do you know the compression ratio you currently have.

If you can get a better than 9.0-1 ratio (Which isn't to bad by itself) , then a base cam that will do the job would be like a purple 280/480 cam. (Or 230* @ 050 and in that area the cam spec should be for the goal at hand.) With the ported heads, headers etc... of which you plan on, it'll do really well.

 

[kb67mopar]

Well I am going to be using a NV3500 5 speed for my transmission, so no automatics here. Rear end I am probably going to shoot for 3:55's or somewhere around there but for a while it will be the stock 2:94's (til the budget allows for the new rear end).

I still haven't torn into the 360 yet to see what I have. I picked it up this summer but have been busy working on getting the floors sealed up for winter. I only have a 1 car garage and I need that open this winter so I have to store the Coronet well wrapped outside this winter (not by want...)

I am assuming a stock style rebuild was performed so probably somewhere in the 8's. But I may be able to bring that up some, just have to tear into it to figure it out. I do like that 340 cam that you mentioned before, I may pop for one of those next year when I start getting into the meat of the engine build.

 

[rumblefish360]

OK... well, mic it up and know the numbers. Overbore, slugs down in the hole at ??? cylinder head cc and then the gasket thickness and bore. (Intended head gasket)

If milling the heads is out, besides a clean up cut, then the 340 replacement can is as big as I would go. If you do not mind milling the head, then a bigger cam is OK. With the 3.5's, the second cam I mentioned is workable with a 26 inch or less tire.

Are you going to document the 3500 install? I'd like to see that one done. It's got a really deep first gear right? And with that being mentioned, a manual trans, go for a DP carb, which IMO works great coupled with a manual trans.

I had a Holey 600 4150 DP on top of a worked up 318 and a 4spd. Once I got that dialed in, wow, what a nice lil'engine that could!

 

[kb67mopar]

Yeah I will have to post once I get the engine apart, I am not sure when I will do that, it may not be til spring.

And of course I will post for the install of the 3500. I still have to pick one up. I have a line on one but I don't know if I am going to be able to pick it up yet. I kinda need to save some money for a little while.

I have a thread in the restorations section under 67 coronet deluxe, so it probably will get lumped into that one as I keep working on it.

I think my holley 750 is a double pumper vac secondary carb. I will have to pull the model number off that again and look it up but i know its got two fuel inlets.

 

[duke51]

If there is only one accelerator pump, its' not a double pumper. If there is a vacuum canister on the passenger side of it, its a vacuum secondary. Simple as that.