Big Block and Firewall Clearance

[65stepside]

Anyone have any issues when putting in a big block and having clearance issues with the firewall? I have a 350 in right now, and with the HEI its super close.

For a big block do you have to cut out the firewall to create more room for the distributor?

thanks

[hewlett2002000]

i put the HEI in mine too and it is very close. the two back plug wires touch the firewall.

[1990SSchevy65]

Most likely both of you guys have your small blocks mounted in the 6cyl position. I remember going to a car show and a guy had a big block in his 65 and the dist looked like it had about two fingered width before touching the firewall.

[hewlett2002000]

well i just pulled my engine so ill check it out and see before it goes back in.

[65stepside]

Originally Posted by 1990SSchevy65

Most likely both of you guys have your small blocks mounted in the 6cyl position. I remember going to a car show and a guy had a big block in his 65 and the dist looked like it had about two fingered width before touching the firewall.

I actually pulled the old V8 283 out about 2 yrs ago, and put the 350 back in the stock mounts. That was in my 65, I now have a 60 with the straight 6 in it that will come out, I'm looking to swap the front crossmember out for a 73-87 crossmember. I was looking on craigslist and found some possible donors, and they just happened to have 454's in them....

So i am kinda wondering if i use the 73-87 crossmembers that already have the 454 if the clear to the firewall will be an issue..

[harry]

no problems with mine just cant use tall rocker covers,everything clears

[65stepside]

Harry, thanks for the info and pics!!! WHat kind of headers are you using there?
thx

[harry]

i have what they call a "budget" heater in my truck which is mounted under the dash on the firewall and it only has a fan and demist,interior control. No hot or cold control !!

[harry]

oops didnt read your question properly,the headers were made at a local exhaust shop in my town and i think i have some pics

[65stepside]

Harry, so did you use the stock mounts for the engine? thx

[harry]

yep,i used the 63 engine mounts off the smallblock when i removed it and bolted them to the BB and it slotted right in.

[65stepside]

Right on you've got a great ride there. Looks like you're using HEI too, right?

[harry]

yep used the hei dizzy out of the smallblock as well

[Tomsriv]

Wow thats some tight header clearance. I hope your motor mounts don't have any flex in them.

[harry]

been driving it around and theres not one part of the exhaust or headers hitting anywhere and i put that down to the mounts on the bellhousing(original) and engine not letting to much movement happen.I have a really lumpy cam in her as well.

[Captainfab]

When I built my '66 Burb with a 454, I wanted to be able to run taller valve covers. So I just moved the engine and trans forward ~2" and fabbed up some custom motor mount brackets. Wasn't too hard to do....had to drill new trans x-member holes anyway with the T400. Also I was still able to use '73-'87 headers.....they wouldn't work if you kept the 4spd though.

[L0WRIDE]

heres my 454 with custom motor mount brackets ,full length hedmen headers

[NF65Fleetside]

since my 350 has a serious rod knock going on Ive been on the prowl for a replacement motor. Found a killer deal on a 454/th400 combo out of a wrecked 80's pick up. I just might be joining the big block crew!

[Chevy Fleetside]

Harry has a 63 and for some reason I think the firewall is differnt then a 65. I could not get my bb to sit back in the orignal holes without cutting the firewall for clearance. Also when getting headers that are not custom made the left stock perch is in the way ( on my truck anyway) I will be updating my thread soon when I get the mounts I ordered and will let you guys know what is going on. http://67-72chevytrucks.com/vboard/s...d.php?t=259536

[NF65Fleetside]

Ok, so could someone lay out straight what all needs to be done or what issues are definete with using stock mounts? It seems that most of you are either using different mounts or repositioning the perch locations. Also seems that 60-63' are different that the 64-66' when it comes to this swap as well. From all of the threads Ive read, just seems that header clearance is the main issue here....but that using a smaller primary would fix this problem. Got a sweet deal on a motor but just dont have the time or $$$ to guess around at how to get that big sucker into my ride.

[wirebiter]

Hey guys,
I am putting a 327 in my 66. It originally came with a 6 and someone swapped the 6 for a 305. They mounted it in the wrong position so the distributor was close to the fire wall. If you look at the frame on each side you will see a series of 3 evenly spaced holes. The back two are for the 6, and the front two are for the 8. Just for any one who cares.
Later
wirebiter

[Chevy Fleetside]

Originally Posted by wirebiter

Hey guys,
I am putting a 327 in my 66. It originally came with a 6 and someone swapped the 6 for a 305. They mounted it in the wrong position so the distributor was close to the fire wall. If you look at the frame on each side you will see a series of 3 evenly spaced holes. The back two are for the 6, and the front two are for the 8. Just for any one who cares.
Later
wirebiter

v8's are set in the rear holes also. Mine is an original V8 truck and that is where it was mounted.. Only differnce I have seen with the 6 is an extra bracket that reaches to the engine.

Shorty headers might work on the BB but i have not idea on that. I want full lenth headers.. And they are 1 3/4 primary tubes not the 2"

[NF65Fleetside]

Aye I just noticed something, almost all of you are running full length headers, do you think the manifold clearance will be an issue with a set of mids/shorties?

[protrash64]

Hey guys, as wirebiter stated...use the front holes. I did this with minor elongation of the mount holes to keep the spacing correct with the old style engine mount. With the small block in you could lose a 6-pack of beer behind the distributor.

[Chevy Fleetside]

i got mine fitted finally.. I used the motormouts on this page. The ones in the middle of the page on the bottom.. http://www.truckandcarshop.com/trucks60_72/t60_097.html This was so I could set the engine back as far as I could. If you move it forward you can just use the later mounts but I thought they were to ugly for me.. I look at ugly in the mirror I don't want to see it in my truck...