302 vs. 351 Maintenance Room

[FlyingCobra]

I'm giving some consideration to switching my plan from a 302 to a 351.

Here's my question: I know that the 351 limits some options with respect to intakes and air cleaners due to space under the hood. For those who have experience working on both, how noticeable is the difference in underhood room with the 351 when doing maintenance?

I can only see the extra deck height really affecting spark plug changes, touching the exhaust system (something I hope not to have to do much), or pulling the heads (something I hope to NEVER have to do). So I can logic away that it might not be too much, but I've not seen both side by side (and didn't spend as much time looking over the 302 powered Mk4 that I saw at Oshkosh last month). I've also only worked on a very small number of SBF-powered vehicles, and I don't think ever a 351.

I started off my automotive wrenching on Jaguar V12s and we currently have a couple of Mercedes so it's not that I can't deal with tighter underhood setups. It's more that part of my design goal is something simple and easy to work on.

Reason for considering the 351 is for more torque since I've figured that I'm going to have to get a different block anyway, and I can still use my same heads on the 351.

A related question for those who have driven both is how noticeable is the extra weight up front from the 351.

[Jeff Kleiner]

I think you've pretty much got it; plugs and header bolts will be a bit more chhallenging (BTW, you realize that 351 requires different headers or J pipes than the 302 in the roadster, right?) but not insurmountable. Weight difference is 50# = or -, or about 10% of engine weight. I've driven both but every car is and feels different so I can't really say what if any of that could be attributed to the 351 vs 302.

Jeff

[FlyingCobra]

I think you've pretty much got it; plugs and header bolts will be a bit more chhallenging (BTW, you realize that 351 requires different headers or J pipes than the 302 in the roadster, right?) but not insurmountable. Weight difference is 50# = or -, or about 10% of engine weight. I've driven both but every car is and feels different so I can't really say what if any of that could be attributed to the 351 vs 302.

If you can't tell how much of the feel difference is attributable to 302 vs 351, then that probably tells me that I'll be fine with either option. My car is going to be pretty lightweight up front anyway with few accessories and aluminum heads.

Yes, I do know that the 351 will require different headers/Jpipes vs. the 302. My kit doesn't ship for a few more weeks so I should still be able to make that change. And if not, then I'm not going to be heartbroken. I haven't decided for sure that I want a 351 and I think I'm going to be happy with either option.

Thanks for the input.

[GFX2043mtu]

91337913369133891339I can’t speak to the 302 but I have a 351 Windsor stroker in my mk4. Header/ spark plug room is not a problem. In my car there is about 3.5”-4” between the heads and the foot box metal. The trick is air filter options. I have a Dart block with a Victor Jr. intake and a Quick fuel 780 carb. Finding the right filter will either require a drop base air filter or one that is 10”-11” wide (round or oval) as it fits up into the hood scoop. Not a big problem but it does require some for thought. The rest of the motor was a drop in with no motor specific clearance issues. I can’t see a 302 being any easier to service then a 351w in the roadster.

[Olli]

I have a 351 based stroker in my MkIV. Plug changes and header installation can be made easier by removing the valve cover on the driver's side. It isn't necessary but just makes it easier.

Olli

[Rich Birkhan]

351/409 TWM Stack Fuel injection no hood clearance issues. I used an aftermarket steel Oil pan. Pulls like a banshee.

[GoDadGo]

Hey Soaring Snake,

Consider strongly going with the 302 style engine if you want form to follow function to aid in maintenance.

A well put together 302, 331, 347 or 363 will be more than capable of scooting your snake down the road while giving you the best clearance in the engine bay. If you want the MOST clearance, then the only way to fly is with a standard Small Block or LS Chevrolet, but tons of modifications and fabrication will be required. With my setup I can reach everything with ease and Shoenfeld IMCA Adjustable Header #161-33 can be adapted but again you will need very strong fabrication skills to pull it off.

Short Dark Side Cobra Video Compelation:
https://youtu.be/_wnHDNgnNqs
https://youtu.be/PCngiKoopkA
https://youtu.be/IGYtX-3p7xk

Going to the Dark Side is not easy unless of course you Like Making & Eating Stone Soup!

Should you choose to join the Dark Side I'll be happy to assist you with all the changes that are required; however, my best recommendation is to go with the 302 Ford style block that has been stroked to either 347 or 363 cubic inches. These combinations will give the most power, easiest serviced, most supported set up while making your build as simple as possible with No Fabrication Required! My pic would be the 363 version since the 4.125" bore better un-shrouds the intake and exhaust valves, plus we all know that there is no replacement for displacement.

Good Luck & Whatever You Build Will Be Great As Long As You Take Your Time & Pay Attention To The Little Details.

Steve

[CraigS]

Yes the 351 is a little harder to get to the driver side rear plug and header bolt. Only a little harder and those are very infrequent. I put my 408 in winter of 2015-16 and haven't touched a plug yet. The 351 was in since 2007 and I maybe had plugs out 4 times. I have an Edelbrock Performer rpm intake (Not air gap), 1/2 inch spacer and a Quickflow carb. No problem at all using a drop base 14" round filter. You do need to be careful that you don't run a distributor w/ a large cap. Besides the extra cubes, the 351 has stronger head bolts, rod bolts, main cap bolts and oil pump drive shaft. I can't see any reason to do a 302 at all.

[KDubU]

Also have a 351 and the only issue is the one header bolt closest to the driver. I also have the air gap manifold and initially thought of going with an oval air filter but instead went with a Spectre 3”x14” round with a drop base. Works great and plenty of torque.

[FlyingCobra]

Appreciate the input. That's making me lean towards the 351 over 302. I'm thinking about going with ATK for the short block (open to other suggestions), I'll give them a call and ask them some questions. Also need to call FFR, which I was going to do with some order changes anyway.

[FlyingCobra]

Hey Soaring Snake,

Consider strongly going with the 302 style engine if you want form to follow function to aid in maintenance.

A well put together 302, 331, 347 or 363 will be more than capable of scooting your snake down the road while giving you the best clearance in the engine bay. If you want the MOST clearance, then the only way to fly is with a standard Small Block or LS Chevrolet, but tons of modifications and fabrication will be required. With my setup I can reach everything with ease and Shoenfeld IMCA Adjustable Header #161-33 can be adapted but again you will need very strong fabrication skills to pull it off.

Short Dark Side Cobra Video Compelation:
https://youtu.be/_wnHDNgnNqs
https://youtu.be/PCngiKoopkA
https://youtu.be/IGYtX-3p7xk

Going to the Dark Side is not easy unless of course you Like Making & Eating Stone Soup!

Should you choose to join the Dark Side I'll be happy to assist you with all the changes that are required; however, my best recommendation is to go with the 302 Ford style block that has been stroked to either 347 or 363 cubic inches. These combinations will give the most power, easiest serviced, most supported set up while making your build as simple as possible with No Fabrication Required! My pic would be the 363 version since the 4.125" bore better un-shrouds the intake and exhaust valves, plus we all know that there is no replacement for displacement.

Good Luck & Whatever You Build Will Be Great As Long As You Take Your Time & Pay Attention To The Little Details.

Steve

Appreciate the offer, Steve, but I won't be going with a GM powerplant. Mostly I don't want to do all of the extra/custom fabrication and I'm more of a Ford guy these days (although I used to be more of a GM guy). I think your 383 build is very cool!

[brewha]

Here’s some pictures of my 331(302 block). A gorilla could get his hands in between the motor and the engine bay.
I’m pushing 395 hp and with 3.55 rear end it can get scary fast pretty quick. Would more weight and hp produce from a 351 block do that much more for drive ability?
91417914189141991420

[CDXXVII]

I really do not see any clearance related challenges with regards to a 351 Windsor engine aside from the intake/air cleaner. I had to replace head gaskets in my finish/painted MK4 and got the job done with no issues. I did have a few choice words about Ford Racing and I did scrape a few knuckles but none related to space issues.

Tons of space. Here is a pic. before paint.

https://thefactoryfiveforum.com/attachment.php?attachmentid=65566&d=1490328828

[FlyingCobra]

Really appreciate the pictures, that helps a great deal. Oh, and very nice engine bays. :)

[David Hodgkins]

CDXXVII, I can't believe you'd post such a disgusting pic. U couldn't even clean the garage floor before taking it?

;)

[johnnybgoode]

Lots of room for 351W based block. Scott

91424

[David Hodgkins]

lots of room for 351w based block. Scott

91424

nice bling!

:)