Put an Edelbrock top end kit on a 1970 cougar convertible with a 351w-2v this summer. Happy with the results, definitely a lot more power. Upgraded the carburetor to an Edelbrock Thunder series 800 cfm, switched the 2v to 4v and added a set of headers/new exhaust. Installed MSD electronics and new wires. Edelbrock carburetors have a nice tuning process so still “fiddling” for the right spring/rod combination but getting pretty close. Also replaced water pump (high volume) and put in a new aluminum radiator (car has A/C and was prone to overheating here in the midwest) since engine had been bored 30 over.
Problems
1)Had to add a hood scoop. Standard air filter no longer fit under the hood and the engine seemed to be starving for air. Tried many different things before I bit the bullet cutting a hole in the hood but glad I did. The hood scoop (found an original eliminator one in great shape) really looks good. 2)The old linkage for the accelerator cable and kick down linkage was difficult to hook up on the carb- eventually went to a Lokar set up (cables/bracket) that looks great.
The kit itself is plug and play. Not sure what the exact hp is now but the car is definitely more responsive and the drive to get ice cream on Saturday nights doesn’t take nearly as long. Next project is to upgrade the brakes which I hadn’t thought would become necessary. Hoping someday to smoke the old 14" tires that I have stored in the garage. Not sure if you need to include the price of new tires:)
Yes, 800 cfm is too large for a relatively stock 351. Are you rebuilding the engine? The Edelbrock carb is not the choice for any performance build. You’re also not going to get 400HP from the kit. I personally would never spent that kind of money without dealing with the bottom end. What do you know about what is there? Not what the previous owner told you but you know for absolute fact.
The problem is that my technical knowledge is very limited. Even though I want to learn more, that needs time.
If someone can help me figure out what is the best bang for the buck I would be open to do something different. but until then those kits look like they are made for someone like me that just wants a bit more power (just for the street) for a few thousand miles a year with great driveability without having any worries.
Absolutely right. For a track car, you might go with a bigger carburetor, but for a street car, forget chasing horsepower numbers on paper anyway. Peak horsepower is fine on a drag strip, but you will find far more satisfaction and enjoyment with an engine that has high average power instead. Being able to make great torque from low RPM all the way to your peak means far more than an engine that bucks, snorts, stalls, and doesn’t know what do do when you stomp the gas from a stoplight, or at part-throttle. You need to tune your car for everyday operation, not just wide open throttle, because literally 99% of your driving will not be at wide open throttle anyway. There are real world limits to how long you can hold down your skinny pedal on a public road.
“Awesome heads, modest cam” is probably the best possible combo for a hot street machine. For your engine, an Edelbrock RPM air-gap and Summit Racing SUM-M08750VS Summit Racing™ M2008 Series Carburetors | Summit Racing Summit carburetor with annular boosters would hold nothing back on the top end, while still giving you a great torque curve even down low. A set of Edelbrock RPM heads would be fine, but if you really want the best, AFR 185’s would be a perfect match for your engine and performance needs. Keeping your compression around 10:1, with something like Comp Cams XE262H, you would have vicious, instant throttle response, brutal top end, and still be able to enjoy it for everyday in-town driving.
Subframe connectors and traction aids would be pretty important if you take your engine this far, despite it being a ‘street’ build.
I had planned on using a Holly 650 cfm but decided to keep everything Edelbrock since I upgraded to their Endurashine finish and wanted the carb to match. Edelbrock states their 400 hp was obtained using their 800 cfm thunder series (Summit web site- response to question on which carburetor to use). JEGS also has a recommendation on their site to use the Edelbrock 800 cfm thunder series for the Edelbrock top end kit. I was surprised an 800 cfm carb was recommended as well. I have wandered how it would have run if I had stuck to my original plan.
Since installing the kit, the car has great acceleration around town. On the highway trips I have taken it on, the engine has performed very well. It definitely has plenty of power and I still have not gotten anywhere near full throttle. I liked that Edelbrock has matched everything in one package and I spent a great deal of time reviewing their kit before I bought it. It probably is overkill for what I use it for but I really like the power that it has. It most certainly is not a cheap product. Guess I started where you are at and decided to stick with a name I knew and was comfortable with. I am glad I have now joined this site so I can have access to so many knowledgeable cougar owners. I enjoy the dialog and look forward to having a place to find answers to questions that I have traditionally searched the internet for and never feeling comfortable in what I found.
The wife thinks I have turned the Sunday driver into a race car but I enjoy the car now more than ever so I would say that the upgrades have been worth it to me. We have had the car for thirty five years. Even after having the engine rebuilt ten years ago it still ran like an old boat that had bad gas. I would definitely not compare it to that anymore.
Sorry to hijack the topic a bit but I was looking at a top end kit for the 302 as well.
Any special prep for the bottom end of the engine before using these kits?
The issue is the chamber size and piston design. The Windsor heads list a 60CC chamber. If you have dished pistons you may wind up with just over 9.0 compression. Too low for any performance application. You also don’t want to put a band aid on a wounded engine. You’ll need to upgrade the ignition, fuel pump and possibly even the cooling system. Anything with more power produces more heat. You’ll want headers as well as a free flowing exhaust.
In my opinion I would go crate engine in your case. Many of us in our youth and lack of disposable income bought cheap bolt on performance parts and as I have got older nothing worse doing the same thing multiple times. Reliability is important and with a family the spare time is limited.
If you don’t short cut this you’ll be happy and you won’t get frustrated with constant mechanical issues.
Just a bit of wisdom from someone who has done this since he was 16.
-Keith
Yes, absolutely. You can’t just slap them on an old low compression engine. They are rated at 250 brake horsepower. Not Net. Edelbrock is smoking crack claiming 400 horsepower with that kit. With many changes perhaps. I am running the factory dual quads on a build 427 with a lot of work and I run factory dual Holleys. ( listed at 600 CFM each, in reality 1104CFM for the pair. There’s no way 800 CFM is going to run well on a mild engine. Those heads aren’t made to produce a substantial amount of horsepower over factory heads, but more on line with a replacement head with some improvement. Again, no way in hell I would bother without knowing what your bottom end is and it’s condition. I have the Edelbrock heads on my 427. Keith Black did the port work, 2.19 Int/ 1.75 Exh and 140 on the seat and 355 open, titanium retainers. The heads do save 55lbs over the iron FE heads. You’ll have to at minimum have the distributor re-curved. There are a lot more offerings aftermarket for small block Ford Vs. the FE.
Use wisdom and avoid shortcuts.
I had a 69 that I built with 10:1 compression, and Edelbrock performer RPM cam and intake, Demon 650 DP Carb (mechanical secondaries).
I had World Products Sr Heads (2.02/1.6 valves) intake and exhaust matched with Hooker Super Comp Headers, MSD ignition.
I had it chassis dynoed at Carlise at 275hp and just under 300 ft/lb torque at the wheels.
I had AOD Trans with 2800 stall and 4.11s, ran a best of 13.20 at 103. https://flic.kr/p/2i95t7C https://flic.kr/p/2i95t84 https://flic.kr/p/2i995dY https://flic.kr/p/2i95vnz
Thanks for your replies. I will think about it, maybe it is better to talk with my mechanic and get the best possible setup for my needs instead of just buying the Edelbrock kit.